Xsan 2 Administrator’s Guide
K Apple Inc. © 2008 Apple Inc. All rights reserved. Under the copyright laws, this manual may not be copied, in whole or in part, without the written consent of Apple. The Apple logo is a trademark of Apple Inc., registered in the U.S. and other countries. Use of the “keyboard” Apple logo (Option-Shift-K) for commercial purposes without the prior written consent of Apple may constitute trademark infringement and unfair competition in violation of federal and state laws.
1 Contents Preface 9 10 10 10 11 11 About This Book What’s New in Xsan 2 Version Compatibility Upgrading from an Earlier Version of Xsan Getting Additional Information Notation Conventions Chapter 1 13 13 14 15 15 15 16 16 17 17 18 19 19 19 19 20 20 21 Overview of Xsan Xsan Storage Area Networks Shared SAN Volumes Metadata Controllers Clients Network Connections How Xsan Storage Is Organized LUNs Storage Pools Affinities Volumes Folders with Affinities How Xsan Uses Available Storage Metadata and Jou
27 27 28 34 35 35 35 35 36 36 36 37 37 37 Outgoing Mail Service Planning Your SAN Planning Considerations and Guidelines Planning the Ethernet TCP/IP Network Using a Private Metadata Network Using Switches Instead of Hubs Planning the Fibre Channel Network Verifying Base Fibre Channel Performance If Your Fibre Channel Fabric Is Running Slower Than Expected Configuring RAID Systems Installing the Latest Firmware Connecting RAID Systems to an Ethernet Network Choosing RAID Levels for LUNs Adjusting RAID S
Chapter 5 59 60 60 61 62 63 63 63 64 64 65 65 65 66 67 67 68 68 69 Setting Up a Folder Affinity Changing a Folder’s Storage Pool Affinity Removing an Affinity Changing Advanced Volume Settings Setting the Block Allocation Size Changing the Volume Allocation Strategy Enabling or Disabling Spotlight on a Volume Enabling or Disabling Access Control Lists Changing the Windows ID Mapping Changing Advanced Allocation and Cache Settings Renaming a Volume Changing Storage Pool Settings Choosing the Data Type for
89 90 90 91 91 Creating Local Home Folders for Network Accounts Accessing Client Computers Remotely Controlling a Client Using Screen Sharing Connecting to a Client Using SSH in Terminal Managing a Client Server Using Server Admin Chapter 6 93 94 95 95 96 97 97 98 98 99 99 99 Managing Metadata Controllers Adding a Metadata Controller Setting Controller Failover Priority Switching to a Standby Controller Finding Out Which Controller Is Hosting a Volume Listing the Volumes Hosted by a Controller Changi
112 113 113 If You’re Unable to Add LUNs to a Storage Pool If the Capacity of a Larger LUN is Listed as 2 Terabytes If File Copying Doesn’t Finish Appendix A 115 115 116 116 117 Combining Xsan Controllers and StorNext Clients Terminology Compatible Software Versions Licensing Using Xsan Controllers with StorNext Clients Appendix B 119 119 119 120 120 120 121 121 124 124 125 126 127 127 128 128 128 130 130 130 131 131 131 Using the Command Line Using the Shell Commands Sending Commands to Remote Compu
Contents
Preface About This Book Use this guide to learn how to use Xsan 2 set up and manage volumes on a storage area network. This guide shows how to use Xsan 2 to combine RAID arrays into large, easy-to-expand volumes of storage that clients use like local disks but are actually shared over a highspeed Fibre Channel fabric. Chapter 1 provides an overview of Xsan and how you can use it to organize RAID arrays into shared volumes of storage.
What’s New in Xsan 2 Xsan 2 offers these new features and capabilities: Â The Xsan Admin application has been redesigned to simplify SAN management. Â You can use Xsan Admin to turn on drive activity lights to identify LUNs. Â A volume setup assistant guides you through the process of creating volumes for common purposes such as video editing and file services. Â The volume setup assistant also organizes available storage into storage pools for you, based on the way you plan to use the volume.
Getting Additional Information For more information about Xsan, consult these resources: Read Me documents (on the Xsan Install Disc) Read important updates and special information Server documentation website (www.apple.com/server/documentation) Get the latest Xsan documentation available in PDF format Xsan website (www.apple.com/xsan) Visit the gateway to extensive product and technology information Xsan Support website (www.apple.
Preface About This Book
1 1 Overview of Xsan This chapter gives you an overview of Xsan and storage area networks. Read this chapter for an overview of Xsan and how you can use it to set up a storage area network (SAN) to provide fast, shared storage. Mac OS X San Volume Storage pools Xsan lets you combine RAID arrays into volumes clients use like local disks.
An Xsan SAN consists of:  Shared data volumes  RAID systems that provide storage space that is protected against disk failure  At least one computer acting as a metadata controller that combines the RAID arrays and presents their storage to clients as one or more volumes that behave like local disks  Client computers that access storage in accordance with established permissions and quotas  Underlying Fibre Channel and Ethernet networks Ethernet (public) Ethernet (private) The following illustration
Metadata Controllers When you set up an Xsan SAN, you assign at least one computer to act as the metadata controller. The controller manages volume metadata, maintains a file system journal, and controls concurrent access to files. Metadata includes such information as where files are actually stored and what portions of available storage are allocated to new files. To guarantee volume availability, a SAN should include more than one metadata controller, as shown in the illustration on page 14.
How Xsan Storage Is Organized Although an Xsan volume mounted on a client computer looks like a single disk, it actually consists of multiple physical disks combined on several levels using RAID techniques. The following illustration shows an example of how disk space provided by the individual drive modules in several RAID systems is combined into a volume that users see as a large local disk.
If the standard RAID arrays on your RAID systems are not right for your application, you can use the RAID system management software to recreate arrays based on other RAID schemes or different numbers of drive modules. For information about other RAID schemes, see “Choosing RAID Schemes for LUNs” on page 30. The illustration on page 16 shows eight RAID array LUNs. The LUN that stores metadata and journal information uses RAID level 1 (mirrored) to ensure against metadata loss.
More than one storage pool may have the same affinity tag. Xsan distributes the contents of a folder with a particular affinity tag among the storage pools that have that same affinity tag. This strategy improves performance when multiple users simultaneously read and write files in the same folder, because the read and write operations are distributed among the storage pools and their component LUNs. You use Xsan Admin to assign affinity tags to storage pools and associate folders with those affinity tags.
Folders with Affinities To control which storage pools are used to store specific files (for example, to provide different levels of service for different users or applications), you can associate a folder on an Xsan volume with an affinity that is assigned to one or more of the storage pools that make up the volume. For example, you can associate some folders with an affinity whose storage pools have faster LUNs, and associate other folders with an affinity whose storage pools have safer LUNs.
Security There are several ways you can control access to a SAN volume: Â Unmount a volume on client computers that shouldn’t have access to it. Users cannot browse or mount SAN volumes; only a SAN administrator can mount SAN volumes on clients. Â Mount a volume on a client for read-only access to prevent users on a particular client computer from modifying data on the volume. Â Specify owner, group, and general access permissions in Xsan Admin.
Xsan Capacities The following table lists limits and capacities for Xsan volumes.
Chapter 1 Overview of Xsan
2 Planning a Storage Area Network 2 This chapter lists Xsan hardware and software requirements and offers planning guidelines and performance tips that can help you design a SAN that meets your needs.
Supported Operating Systems You can install Xsan 2 only on computers with Mac OS X v10.5 Leopard or Mac OS X Server v10.5 Leopard. Mac client computers that have Xsan 1.4.2 can join an Xsan 2 SAN. These clients can have Leopard or Tiger. To join an Xsan 2 SAN, Windows, AIX, IRIX, Linux, and Solaris clients must be running Quantum’s StorNext File System version 2.6 or 2.7. For complete compatibility information, see “Version Compatibility” on page 10.
Fabric Configuration You must connect the computers, storage devices, and switches in your Fibre Channel network to form a Fibre Channel “fabric.” All Apple-approved switches create a fabric by default as soon as you plug in the Fibre Channel cables. In a fabric, Fibre Channel cables connect node ports (F or N_Port). See the documentation that came with your Fibre Channel switches for more information. Ethernet TCP/IP Network Computers on the SAN must also be connected to an Ethernet network.
Directory Services If you plan to use user and group privileges to control access to files and folders on the SAN, you should set up or join a central directory of users and groups. A central directory service lets you manage all SAN users and groups from one computer instead of having to visit and painstakingly configure each SAN client and metadata controller.
Important: If you create users and groups on each SAN computer, be sure that: Â Each user or group has a numeric user ID (UID) or group ID (GID) that is unique throughout the SAN Â Each user or group defined on more than one computer has the same UID or GID on each computer Outgoing Mail Service Xsan can send SAN status notifications via email on your local network (IP subnet) without using a separate mail server.
     How do you want to present available storage to users? What storage organization makes the most sense for user workflow? What levels of performance do your users require? How important is high availability? What are your requirements for security? Your answers to the above questions will help you decide the following:  What RAID schemes should you use for your RAID arrays?  How many SAN volumes do you need?  How should individual volumes be organized?  Which preset volume type can you choose
How Should Users See Available Storage? If you want the users working on a particular project to see a volume dedicated to their work, create a separate volume for each project. If it’s acceptable for a user to see a folder for his or her work on a volume with other peoples’ folders, you can create a single volume and organize it into project folders.
 Choose a different primary metadata controller for each volume, and set up volume failover priorities to minimize the possibility of more than one volume failing over to the same metadata controller. Availability Considerations If high availability is important for your data, set up at least one standby metadata controller in addition to your primary metadata controller.
Most RAID systems support all popular RAID levels. Each RAID scheme offers a different balance of performance, data protection, and storage efficiency, as summarized in the following table.
Assigning LUNs to Affinity Tags When you create a volume using a preset volume type that fits your SAN scenario, Xsan Admin automatically sets up storage pools and affinity tags for best performance. All you do is assign LUNs to each affinity tag. Xsan Admin determines the optimal number of storage pools to create, based on the volume type and the number of LUNs you assign to each affinity tag. For best performance, you should assign LUNs in the multiples shown below.
Choosing Metadata Controllers You must choose at least one computer to be the SAN metadata controller, the computer that is responsible for managing file system metadata. Note: File system metadata and journal data are stored on the SAN volume, not on the metadata controller itself. For more information, see “Choosing Where to Store Metadata and Journal Data” on page 33.
If you set up a custom volume with more than one storage pool, you can choose which storage pool is used to store metadata and journal data. You may get adequate performance by combining metadata and journal data on the same storage pool as user data, but for better performance, use a separate storage pool for metadata and journal data.
 Use two separate networks—one for metadata and another for all other IP traffic. This configuration is slightly more expensive (requiring two Ethernet adapters for each computer) but offers greater security and better performance because routine network traffic doesn’t interfere with SAN volume metadata traffic. Using a Private Metadata Network Non–SAN-related Ethernet traffic can interfere with the exchange of metadata among Xsan controllers and clients.
If Your Fibre Channel Fabric Is Running Slower Than Expected The following paragraphs list things you can check if your Fibre Channel fabric is not running at the expected 2 GB/s. Check Cables One faulty cable in a fabric can slow the entire network. Check all cables to make sure they are capable of full transmission speed. Use your switch management software to isolate the faulty cable by checking the performance of specific connections.
Connecting RAID Systems to an Ethernet Network For best performance, don’t connect RAID controller Ethernet management ports to the SAN’s metadata network. Connect the ports to the separate Ethernet network that you use for other types of network traffic, such as directory services, Internet access, and remote Xsan management. Choosing RAID Levels for LUNs Use RAID 1 for metadata LUNs and RAID 5 for data LUNs.
When RAID controller write caching is enabled, a request to write data is considered finished as soon as the data is in the cache. This is sometimes called “write-back caching.” Write requests are processed more quickly because the file system just needs to write to the fast cache memory and doesn’t need to wait for the slower disk drives. Be sure to enable write caching on RAID controllers that support metadata storage pools. Although some large write requests might benefit from caching, often they don’t.
3 Setting Up a Storage Area Network 3 This chapter shows step by step how to set up a shared volume on an Xsan SAN. This chapter explains how to connect the SAN networks, prepare RAID arrays (LUNs), use the Xsan Admin application, set up a new SAN, and create a shared volume. This chapter also tells you how to administer Xsan remotely, rename a SAN, remove a SAN, set up additional SANs, and manage multiple SANs.
Using Server Assistant to Configure Controllers You can use the Mac OS X Server setup assistant, Server Assistant, to configure servers as Xsan metadata controllers. Server Assistant runs automatically when you start up a new server or a server on which you have performed a clean installation of Mac OS X Server v10.5 Leopard. When using Server Assistant to set up your primary metadata controller, you can choose how you will manage Xsan users and groups.
Using Xsan Admin You use the Xsan Admin application (installed in /Applications/Server/) to set up and manage your SAN. You can use Xsan Admin to manage an Xsan 2 SAN from any computer that has access to the same public intranet as the SAN. Installing Just the Xsan Admin Application You can install Xsan Admin on any computer you want to use to manage the SAN. See “Setting Up an Xsan Administrator Computer” on page 51.
Setting Up an Xsan Volume on a Storage Area Network Step 1: Set Up the Fibre Channel Network m Connect controller computers, client computers, and RAID storage systems to a Fibre Channel switch to create a Fibre Channel fabric for the SAN. Be sure to configure the switch and make the connections so that you create a Fibre Channel fabric. For more information, see the guidelines and requirements under “Fibre Channel Fabric” on page 24.
Step 3: Configure SAN Computers to Use a Time Server m To ensure consistent time metadata across all computers in the SAN, open Date & Time preferences and choose the same network time server for all metadata controller and client computers. If you’re setting up a new server or a computer on which you have performed a clean installation of Leopard Server, you can choose a network time server in the Time Zone pane of the Mac OS X Server setup assistant.
Later, in the “Add User Accounts” pane, you have the option of creating some user accounts. The Mac OS X Server setup assistant creates the user accounts in the LDAP directory of the Open Directory server it creates on your primary metadata controller. After setup, you use Xsan Admin to create and delete users and groups and to change group membership. For information about Open Directory servers, see “Directory Services” on page 26.
New RAID systems are usually preconfigured as a set of RAID arrays that are ready to use as LUNs. For help choosing other RAID schemes, see “Choosing RAID Schemes for LUNs” on page 30. Step 6: Create a Metadata Array Ten gigabytes (GB) of disk space is enough to store the metadata for a volume containing 10 million files, so a two-drive RAID 1 (mirrored) array is generally large enough to store the metadata for your SAN volume.
If you’re setting up new metadata controller, or a controller on which you have just performed a clean installation of Leopard Server, the setup assistant prompts you to insert the Xsan Install Disc when it’s time to install the Xsan software. 2 In the Custom Install pane, deselect Xsan Admin, click Continue, and follow the remaining onscreen instructions to install just the Xsan file system.
Step 8: Configure the SAN You use Xsan Admin to configure the SAN. The first time you use Xsan Admin on a computer, it automatically starts the Xsan setup assistant. 1 Open Xsan Admin (in /Applications/Server/). Xsan Admin opens automatically when you finish installing the Xsan software on your primary metadata controller computer. You can also open Xsan Admin on any computer with an intranet or Internet connection to your SAN computers.
 Use same authentication information for all SAN computers: Select this option to have Xsan Admin authenticate to all computers using the administrator name and address you enter in this pane.  Authenticate to SAN computers one by one: Select this option to authenticate to each computer individually. 7 In the Serial Numbers pane, enter your Xsan serial numbers. You can click Add Serial Number and type a number, or drag a text file containing serial numbers to the list.
Step 9: Create a Volume When the Xsan setup assistant finishes basic SAN configuration, it asks if you want to set up a volume. 1 In the “Create Volume” pane, select “Create a volume now” and click Continue. If you want to set up volumes later, follow the instructions under “Adding a Volume to a SAN” on page 58. 2 In the “Volume Name and Type” pane, type a name for the volume and choose a volume type that matches the type of work the volume will support. Optionally, click Advanced Settings.
 Spotlight: Enable this if you want Macintosh clients to be able to search the contents of the volume using Spotlight.  Access Control Lists: Leave this enabled if you want to use access control lists in Xsan Admin to control access to the volume and its contents.  Windows ID Mapping: If you will have Windows clients on your SAN, choose how they map user and group information to the Xsan-compatible user IDs and group IDs they need in order to access this volume.
For information about creating additional volumes, see “Adding a Volume to a SAN” on page 58. Step 10: (Optional) Customize SAN Status Notifications Xsan is set initially to notify the administrator by email when the status of the SAN changes. You can have notifications sent to additional email addresses or textmessaging addresses, and you can choose conditions that trigger notification to each address. If you don’t want to customize notifications now, you can do it later.
Removing a SAN Follow these steps to take a SAN out of service, removing its metadata controllers, clients, and volumes. WARNING: Removing a SAN destroys its volumes. Data stored on the volumes is no longer available. To remove a SAN: 1 If you want files located on the SAN volumes to be available after you remove the SAN, back up the files. 2 Open Xsan Admin (in /Applications/Server/) and click Overview. 3 Choose Destroy SAN from the Action (gear) pop-up menu.
4 Managing SAN Storage 4 You can use Xsan Admin and related command-line tools to expand, add, modify, check, and repair SAN volumes. This chapter shows how you can expand an existing Xsan volume to provide more free space. It also contains information on volume and storage pool settings, and shows how to check and resolve volume integrity and fragmentation problems.
Preparing LUNs Each LUN in an Xsan volume is a RAID array. The way you set up your arrays depends on the storage device you are using. If you’re adding new RAID systems to your SAN, they may be ready to use right out of the box. Many RAID systems ship already configured as one or more RAID arrays, and each array should appear in the Xsan setup assistant as a usable LUN.
Adding LUNs to a Storage Pool You can increase the size of a SAN volume by adding LUNs (RAID arrays or array slices) to storage pools in the volume. If you’re expanding a volume that is based on a built-in volume type, you add LUNs to affinity tags and Xsan Admin assigns the LUNs to underlying storage pools for you. If you’re expanding a custom volume, you add LUNs directly to storage pools.
To add a LUN to a storage pool: 1 If you haven’t already done so, connect the RAID system that hosts the LUN to the SAN Fibre Channel network and power on the device. 2 In Xsan Admin, select Volumes in the SAN Assets list. 3 Select the volume in the list and choose Expand Volume from the Action (gear) pop-up menu. 4 In the Label LUNs pane of the assistant, choose whether you want to label unlabeled LUNs individually or sequentially based on a label prefix.
Adding a Storage Pool to a Volume You can add free space to a SAN volume by adding a storage pool to the volume. If you’re expanding a volume that is based on a built-in volume type, you actually create a new affinity tag and add LUNs to it. Xsan Admin creates and organizes new storage pools within that tag for you. If you’re expanding a custom volume, you create new storage pools directly and add LUNs directly to them.
Adding a Volume to a SAN A single Xsan SAN can provide access to multiple volumes. Select to view current volumes. Click to add a new volume. To add a volume: 1 In Xsan Admin, select Volumes in the SAN Assets list and click the Add Volume (+) button. 2 In the Volume Name and Type pane of the assistant, type a name for the volume and choose a volume type that matches the kind of work the volume will support. Xsan Admin sets the underlying volume settings accordingly.
Setting Up a Folder Affinity Every storage pool in a volume has an affinity tag. You can use the tag to be sure that files in a folder are stored on a particular storage pool. Files folders without affinities are stored in the next available storage pool according to the volume’s allocation strategy. You might have some storage pools that are larger, faster, or better protected than others.
Changing a Folder’s Storage Pool Affinity You can use Xsan Admin to change a folder’s affinity so all new files placed in the folder are stored on a new storage pool. To change a folder affinity: 1 In Xsan Admin, select File Management in the SAN Assets list. 2 Select the folder, choose Set Affinity from the Action (gear) pop-up menu, and then choose the new affinity tag. 3 Click OK. Files already in the folder are not automatically moved to the new storage pool.
Changing Advanced Volume Settings If your SAN volume has special configuration requirements, you can change the standard volume settings when you create a volume. You can also change these settings for an existing volume, with the exception of the volume name and block allocation size. Note: To change a volume’s name or block allocation size, you must destroy and recreate the volume.
Setting the Block Allocation Size Xsan uses the volume block allocation size together with the storage pool stripe breadth to decide how to write data to a volume. If you create a volume based on a built-in volume type (for example, General File Server or Calendar Server Cluster), Xsan Admin sets optimal values for you. For most volumes, the preset block allocation size and storage pool stripe breadth result in good performance.
Changing the Volume Allocation Strategy You can change the allocation strategy for a volume to choose how storage for new files or additional storage for existing files is allocated on the storage pools that belong to the volume. Â Round Robin: Each new request for space is assigned to the next available storage pool in the volume. Â Fill: All data is stored on the first storage pool until it is full, then on the next storage pool, and so on.
Changing the Windows ID Mapping If you have Windows clients on your SAN, this setting determines how they map user and group information to the Xsan-compatible user IDs and group IDs they need in order to access this volume. For more information, see “Mapping Windows User and Group IDs” on page 84.
Renaming a Volume To change the name of a volume, you need to reinitialize the volume with the new name. You can’t rename an Xsan volume using the Finder. WARNING: Reinitializing a volume destroys all information stored on the volume. To rename a volume: m In Xsan Admin, select Volumes in the SAN Assets list, select the Volume, and choose Reinitialize Volume from the Action (gear) pop-up menu.
Setting the Storage Pool Stripe Breadth Xsan uses both the storage pool stripe breadth and the volume block allocation size to decide how to write data to a volume. For most SANs, the default values for storage pool stripe breadth and volume block allocation size result in good performance. However, in some cases you might be able to improve read and write performance by adjusting these values to suit a specific application.
Checking Volume Fragmentation When you create a file, Xsan divides the file into pieces and distributes these pieces efficiently over the LUNs that make up one of the volume’s storage pools. Over time, as the file is modified, its pieces become scattered in less efficient arrangements. You can use the cvfsck utility to check the state of file fragmentation on your volumes. To check volume fragmentation: 1 Open Terminal (in /Applications/Utilities/).
Checking the Integrity of a Volume If SAN users are having trouble accessing files, you can use the cvfsck command to check the integrity of a volume, its metadata, and its files. To check a volume: 1 Open Terminal (in /Applications/Utilities/). 2 If you are not working at the SAN controller computer, use SSH to log in to the controller remotely: $ ssh user@computer where user is an administrator user on the controller computer and computer is the controller’s name or IP address.
4 Check the volume to see if additional repairs are required: $ sudo cvfsck -vn volume 5 If the report generated in the previous step lists additional problems, type the following command to perform a full check and repair of the volume: $ sudo cvfsck -vw volume For more information about this command, see the cvfsck man page. Destroying a Volume You can destroy a volume so you can reuse its LUNs to create new volumes.
Chapter 4 Managing SAN Storage
5 Managing Clients and Users 5 You can use Xsan Admin and related command-line tools to add, control, and remove client computers and their users. Xsan clients are computers that have Fibre Channel connections to a SAN. SAN users log in to client computers to access files stored on SAN volumes. This chapter shows you how to add clients, control client access to volumes, and manage user quotas.
Adding a Client Before a computer can use a SAN volume, you need to add the computer to the SAN as a client. These instructions show you how to add a client computer to an existing SAN. Select to view computers already in SAN. Add button To add a client computer to a SAN: 1 Connect the client to the SAN’s Fibre Channel and Ethernet networks. 2 Install the Xsan software on the client. 3 Open Xsan Admin, select Computers in the SAN Assets list, and click the Add (+) button.
Adding an Xsan Serial Number If you have purchased additional Xsan software serial numbers for client computers that you want to add to your SAN, you can enter the numbers in Xsan Admin. Select to view current serial numbers. Add button To add an Xsan serial number: 1 In Xsan Admin, select Serial Numbers in the SAN Assets list. 2 Click the Add (+) button. 3 Type the serial number, registered owner, and organization information provided by Apple, and then click OK.
Moving a Client to a Different SAN You can move a client from one Xsan SAN to a different SAN on the same Ethernet subnet and Fibre Channel network. To move a client computer to a different SAN: 1 In Xsan Admin, select Computers in the SAN Assets list. 2 Select the computer in the list and choose “Remove computer from SAN” from the Action (gear) pop-up menu. 3 In Xsan Admin, open the window for the SAN you want to move the computer to.
Mounting a Volume on a Client Volumes are automatically mounted on SAN computers when you create the volumes. If, however, you explicitly unmount a volume from a client, you need to mount it again in order to restore access. Select the volume Select to view computers that don’t have the volume mounted. Mount Read & Write button To mount an Xsan volume on a client: 1 In Xsan Admin, select Mounts in the SAN Assets list. 2 Select the client in the list. 3 Select the volume in the Volume pop-up menu.
Changing Mount Options You can use Xsan Admin to adjust settings that can affect volume access performance. To change mount options: 1 In Xsan Admin, select Mounts in the SAN Assets list. 2 Select the client in the list. 3 Select the volume in the Volume pop-up menu. 4 Choose Edit Mount Options from the Action (gear) pop-up menu. Directory cache size: Controls the number of file system directory entries that are cached on the client for each SAN volume.
Managing Users and Groups Depending on how you first set up your SAN, you can manage users and groups using either Xsan Admin or Mac OS X Server’s Workgroup Manager. Managing Users and Groups with Xsan Admin When you first set up your SAN controllers, you can use Xsan Admin to manage your SAN user and group accounts. An Open Directory master is created on your primary metadata controller, with replicas on your standby controllers. You can then use Xsan Admin to create and remove user and group accounts.
Adding SAN Users Only users in the SAN’s directory can log in to a client computer and access Xsan volumes. You can use Xsan Admin to add users to your SAN. Select to view current SAN users. Add button Note: These instructions apply only if, during initial SAN setup, you chose to use Xsan Admin to manage users and groups. If you have a different directory configuration, use the management software for your directory to add user accounts.
Deleting SAN Users Only users in the SAN’s directory can log in to a client computer and access Xsan volumes. You can use Xsan Admin to delete users from your SAN directory. Note: These instructions apply only if, during initial SAN setup, you chose to use Xsan Admin to manage users and groups. If you have a different directory configuration, use the management software for your directory to delete user accounts. To delete a user: 1 In Xsan Admin, select Users and Groups in the SAN Assets list.
Changing Group Membership You can use Xsan Admin to change the members of a group at any time. Note: These instructions apply only if, during initial SAN setup, you chose to use Xsan Admin to manage users and groups. If you have a different directory configuration, use the management software for your directory to modify group membership. To change a group’s membership: 1 In Xsan Admin, select Users and Groups in the SAN Assets list.
3 Select the file or folder you want to protect and choose Set Permissions from the Action (gear) pop-up menu. Unmounting a Volume on a Client To prevent a client from accessing a volume, you can unmount the volume from the client. Clients can’t mount SAN volumes themselves; only an administrator can mount a SAN volume on a client. Select the volume. Select to view computers that currently have the volume mounted.
Restricting a Client to Read-Only Access To prevent a user on a client computer from modifying data on a SAN volume, you can mount the volume on the client with read-only access. Select the volume. Select to view computers that don’t have the volume mounted. Action menu To mount a volume with read-only access: 1 In Xsan Admin, select Mounts in the SAN Assets list. 2 Choose the volume from the Volume pop-up menu. 3 Select the client. 4 Choose Mount Read Only from the Action (gear) pop-up menu.
Removing a Client from a SAN You can remove a client computer from a SAN to prevent it from accessing SAN volumes. Select to view computers already in SAN. Action menu To remove a client from a SAN: 1 In Xsan Admin, select Computers in the SAN Assets list, select the client, and choose “Remove computer from SAN” from the Action (gear) pop-up menu. If SAN volumes are mounted on the client, Xsan Admin unmounts them automatically.
Mapping Windows User and Group IDs You can use the Windows ID Mapping setting for a volume to specify how Windows clients map user and group information to Xsan-compatible user IDs (UIDs) and group IDs (GIDs), which they need in order to access Xsan volumes. Note: To use ID mapping, Windows clients must be running StorNext 2.7. Xsan controllers and clients must be running Xsan 1.4.2 or later.
Setting SAN User and Group Quotas You can use Xsan Admin to set quotas to manage the amount of storage available to a user or group. To set a storage quota for a user or group: 1 In Xsan Admin, select Users and Groups in the SAN Assets list. If you’re not using Xsan Admin to manage users and groups, you’ll see Quotas in the SAN Assets list instead of Users and Groups. 2 Choose a volume from the Volume pop-up menu. 3 Select a user or group in the list.
If your Xsan computers connect to another Mac OS X Server for user and group accounts, use Workgroup Manager or Server Preferences to create users and groups as needed. If existing users and groups aren’t listed when you click the Add button, open Directory Utility (in /Applications/Utilities/) on your computer and make sure it’s connected to the correct server for authentication. All computers in the SAN should use the same directory service.
Example Suppose you assign Aldo a soft quota of 75 GB, a hard quota of 100 GB, and a grace period of 48 hours. Aldo’s files can occupy up to 75 GB of space at any time, for as long as he needs them. If Aldo is surprised by additional or unusually large files, he can still copy them to the volume, up to a total of 100 GB. He then has 48 hours to remove files and return below the 75 GB soft limit.
To view quota status: m In Xsan Admin, select “Users and Groups” or Quotas in the SAN Assets list. (You see Users and Groups only if you chose to have Xsan Admin manage your users and groups. Otherwise, you see Quotas instead.) To be sure you’re seeing current information, click Refresh at the top of the window. Xsan Admin displays the following information for each user or group: Â Used: The amount of space the user’s files are occupying. Â Quota: The soft and hard quotas.
Helping Clients Check Their Own Quotas SAN users who work on client computers but don’t have access to Xsan Admin can use the Xsan User Quotas application to check their own quotas. To check your quota from a client computer: m Open the Xsan User Quotas application (in /Applications/Server/). Creating Local Home Folders for Network Accounts Using a centralized directory simplifies the job of managing user accounts for client computers attached to the SAN.
Accessing Client Computers Remotely Xsan Admin can help you connect to an Xsan client computer so you can observe or control it over the network. Using Xsan Admin, you can: Â Start a screen sharing session so you can observe or control another computer. Â Open Terminal so you can log in using SSH and control another computer. Â Connect to and manage another server on the network using Server Admin.
If you have trouble sharing the screen of a remote computer, check the Sharing pane of System Preferences on the remote computer and make sure Remote Management service is turned on. If you have trouble starting a screen sharing session with an Xsan client, open Security preferences on the client, click Firewall, and make sure the option to block all incoming connections isn’t selected.
Chapter 5 Managing Clients and Users
6 Managing Metadata Controllers 6 To increase SAN security and redundancy, you can add, switch, and monitor Xsan metadata controllers. Every SAN volume you set up is managed by a metadata controller. To be sure that the volume is available to clients even if the primary metadata controller becomes unresponsive, you can set up standby controllers, one of which will assume control of the volume if the primary controller fails.
Adding a Metadata Controller You can add one or more standby controllers to a SAN so that volumes are still available if the primary controller fails. Any computer set to act as a metadata controller can also function as a client. So, if you don’t want to dedicate a computer to act solely as a standby controller, you can use an existing client. Select to view computers in SAN. Click to add a new computer.
Setting Controller Failover Priority When the primary metadata controller for a volume fails, Xsan uses the failover priorities of the available standby controllers to decide which one to switch to. To set a metadata controller’s failover priority: 1 Open Xsan Admin, select Volumes in the SAN Assets list, and choose Edit Failover Priority from the Action (gear) pop-up menu. 2 Drag metadata controllers up or down in the list that appears.
Finding Out Which Controller Is Hosting a Volume Control of a volume can move from one metadata controller to another as a result of controller failover. You can use Xsan Admin to find out which controller is currently hosting a volume. The controller that is hosting the volume To view a volume’s controller: m In Xsan Admin, select Volumes in the SAN Assets list and look in the Hosted By column.
Listing the Volumes Hosted by a Controller You can use Xsan Admin or the cvadmin command to find out which SAN volumes are being hosted by a particular metadata controller. To list hosted volumes: m In Xsan Admin, select Volumes in the SAN Assets list, and click the title of the Hosted By column to sort by controller. From the Command Line You can also find out which volumes are hosted by a controller using the cvadmin select command in Terminal.
Accessing Controller Computers Remotely Xsan Admin can help you connect to an Xsan controller so you can observe or control it over the network. Using Xsan Admin, you can: Â Start a screen sharing session so you can observe or control another computer. Â Open Terminal so you can log in using SSH and control another computer. Â Connect to and manage another controller or client on the network using Server Admin.
Connecting to a Controller Using SSH in Terminal You can use the Secure Shell (SSH) tool from the command line to log in to a SAN controller over the network. To connect to a controller using SSH: 1 In Xsan Admin, select Computers in the SAN Assets list. 2 Select the controller you want to connect to. 3 Choose “Connect using ssh” from the Action (gear) pop-up menu.
Chapter 6 Managing Metadata Controllers
7 Monitoring SAN Status 7 You can use Xsan Admin and related command-line tools to check the condition of a SAN and its components. This chapter shows you how to check the status of a SAN and its volumes and how to set up automatic notifications so you’ll be alerted to changes in the SAN. Checking SAN Status You can use Xsan Admin to view status and configuration information for the SAN and its components.
To view a component’s status and configuration information: m Open Xsan Admin, click the Inspector button at the top of the window, and then select the component in the SAN Assets list or the main pane of the Xsan Admin window. Checking Volume Status You can use Xsan Admin to view the status of a volume. To get a quick look at the status of a volume: m Open Xsan Admin, select Volumes in the SAN Assets list, select the volume, and click the Inspector button at the top of the window.
Checking Free Space on a Volume There are several ways to see how much space is available on a SAN volume. Available space To check the free space on a volume: m From a client or controller computer that has the volume mounted, select the volume in a Finder window and look at the size information at the bottom of the window (in Column or List view) or choose File > Get Info.
Checking Free Space on a Storage Pool In addition to checking free space on a volume, you can check free space on individual storage pools in the volume. To check the free space on a storage pool: m Open Xsan Admin, select Volumes in the SAN Assets list, select a storage pool, and then click the Inspector button at the top of the window. If you don’t see the storage pools for a volume, click the volume’s disclosure triangle.
To view usage graphs: m In Xsan Admin, click the Graphs button at the top of the window. Use the three pop-up menus in the Graphs window to choose a computer, a data type, and a time interval. Memory and CPU resources used by the file system (fsm) process for a volume are listed under the name of the volume in the Graphs pop-up menu when you choose the volume’s controller from the Computer pop-up menu.
Viewing Xsan Logs You can use Xsan Admin to view the informational and diagnostic messages that Xsan writes to a computer’s system and log. To view the SAN logs: m In Xsan Admin, click the Logs button at the top of the window. In the Logs window that appears, use the Computer and Log pop-up menus to choose the log you want to view. To display just entries containing specific names, times, or other text, type in the Search field in the lower-right corner of the window.
Checking Volume Clients You can use Xsan Admin to see a summary of which clients are using a volume. To see how many clients have a volume mounted: m Open Xsan Admin and select Volumes in the SAN Assets list. Select the volume in the list and click the Inspector button at the top of the window. To see which clients are using a volume: m Open Xsan Admin, select Mounts in the SAN Assets list, and choose the volume from the Volume pop-up menu.
Checking for Fibre Channel Connection Failures Fibre Channel connection failures or errors are recorded in the system log. To view the system log: m In Xsan Admin, click the Logs button at the top of the window. In the Logs window that appears, choose the computer in the Computer pop-up menu and choose System Log from the Log pop-up menu.
8 Solving SAN Problems 8 This chapter provides solutions to common problems you might encounter while working with a SAN. Look here for solutions to common problems you might encounter while setting up, managing, or using an Xsan SAN. If You’re Unable to Connect to a Computer Using Xsan Admin If there is a firewall between the administrator computer and the SAN computer, make sure TCP port 311 is open.
If You’re Unable to Mount a Volume on a Client  Try restarting the client computer, and then try again.  Check that all Fibre Channel cables are plugged in.  Make sure there are no other volumes mounted on the client that have the same name as the Xsan volume. If RAID LUNs Aren’t Accessible over Fibre Channel  Try restarting the computer that doesn’t see the LUNs.  Check the configuration of the Fibre Channel switch to be sure the SAN components are in the same Fibre Channel zone.
If You’re Unable to Add a Storage Pool There are some reserved names you can’t use to name a storage pool. If you enter one of these names, the OK button in the storage pool sheet is disabled.
If a Client is Unable to Use a Volume After a Fibre Channel Interruption If a client loses its Fibre Channel connection to the SAN (because a cable is unplugged, for example), the client might not recognize LUNs in an Xsan volume after the connection is restored. If this happens, restart the client to remount the volume. If problems persist, restart all SAN devices. Restart RAID systems first, then continue with SAN controllers, and finally, restart all clients.
If the Capacity of a Larger LUN is Listed as 2 Terabytes If a LUN that doesn’t yet belong to a storage pool is listed in Xsan Admin with a capacity of 2 TB, even though you know it is larger (which can happen if you used the LUN with an earlier version of Xsan), try relabeling the LUN. To relabel a LUN: 1 In Xsan Admin, select LUNs in the SAN Assets list. 2 Click LUNs, select the LUN in the list, and choose Remove LUN Label from the Action (gear) pop-up menu.
Chapter 8 Solving SAN Problems
Combining Xsan Controllers and StorNext Clients A Appendix A This appendix shows how to connect Windows, Solaris, UNIX, AIX, IRIX, or Linux clients to an Xsan SAN. Xsan is fully compatible with Quantum’s StorNext File System, so you can set up Xserve and RAID systems to act as SAN controllers and storage for Windows, Sun Solaris, UNIX, IBM AIX, SGI IRIX, or Linux clients that are running StorNext FX software.
Compatible Software Versions This table shows which versions of Xsan and StorNext controllers and clients can be used on the same SAN. Controller Client Compatible Xsan 2 StorNext FX 1.4 or 2.0 Yes StorNext FX 1.3 No StorNext FS/FX 2.4–3.1 No StorNext FS 3.1 StorNext FS 3.0 StorNext FS 2.8 StorNext FS 2.4–2.7 Xsan 2 Yes Xsan 1.4–1.4.2 Yes Xsan 2 No Xsan 1.4–1.4.2 Yes Xsan 1.4.1–1.4.2 and Xsan 2 No Xsan 1.4 Yes Xsan 1.4–1.4.
Using Xsan Controllers with StorNext Clients You can use Quantum’s StorNext software to access an Xsan SAN from a Windows, UNIX, Sun Solaris, IBM AIX, SGI IRIX, or Linux computer. 1 Connect the non-Macintosh client to the SAN’s Fibre Channel and Ethernet networks. 2 Install the StorNext File System software on the non-Macintosh client following the instructions that Quantum provides in the StorNext package. 3 Duplicate the Macintosh Xsan controller’s shared secret file on the non-Macintosh client.
Appendix A Combining Xsan Controllers and StorNext Clients
Using the Command Line B Appendix B This appendix describes Xsan shell commands and configuration files you can use to work with a SAN from the command line. You can use the shell commands and configuration files described here to access, set up, and manage Xsan SANs, LUNs, storage pools, and volumes from the command line. The Terminal application is the Mac OS X gateway to the BSD command-line interface (UNIX shell command prompt).
Viewing the Man Pages Detailed documentation for Xsan command-line utilities is available in UNIX-style man pages. A command’s man page includes information about the command, its options, parameters, and proper use. The man pages for Xsan commands are located in /Library/Filesystems/Xsan/man/. To view a man page, type: $ man command where command is the command you want to information about.
5 Run the installer on the headless computer: Â If you want to install the Xsan file system and Xsan Admin application, enter: $ sudo installer -pkg /tmp/Install\ Xsan.mpkg -target / Â If you want to install just the Xsan file system, enter: $ sudo installer -pkg /tmp/Install\ Xsan.mpkg/Contents/Installers/ XsanFileSystem.mpkg/ -target / Â If you want to install just the Xsan Admin application, enter: $ sudo installer -pkg /tmp/Install\ Xsan.
To execute a single command and return to the shell prompt: $ sudo cvadmin [-H host] [-F volume] -e ["]command [cmdparam..."] Parameter Description -H host The metadata controller that is hosting the volume. If not provided, the local computer is assumed. host – the IP address or DNS name of a metadata controller other than the one on which you are logged in. -F volume The volume to be the active (“selected”) volume in cvadmin.
cvadmin command Description quotas [yes|no] Enable or disable quotas for the active (selected) volume. Use the command without any parameters to see the current setting for quotas. quotas get (user|group) name Display current quota information for a user or group. name – the name of the user or group quotas set (user|group) name hard soft grace Set quotas for user or group name.
Manipulating Affinity Tags (cvaffinity) Use the cvaffinity command to assign an affinity tag to a folder or a file, or to list the affinity tag currently assigned to a folder or a file. Assigning an affinity tag to a folder or file causes it to be stored on a storage pool that has the same affinity tag. You can see the affinity tags for available storage pools by using the show long command of the cvadmin tool.
Option Description -v Report all information about file copied. -x Retain original file permissions in the copy. -y Retain ownership and group information in the copy. This works only if the root user is performing the copy. -z Retain original modification times in the copy.
Option Description –w Modify the file system as needed to repair problems. -x Report statistics in comma-separated form for use in a spreadsheet. Labeling, Listing, and Unlabeling LUNs (cvlabel) Use the cvlabel command to initialize LUNs so they can be added to storage pools. For details, see the cvlabel man page.
Creating a Folder and Assigning an Affinity (cvmkdir) Use the cvmkdir command to create a folder (directory) and assign it an affinity tag so that its contents are stored on storage pools with the same affinity tag. $ cvmkdir -k affinity folder Parameter Description -k affinity Specifies the affinity tag to be associated with the folder.
Initializing a Volume (cvmkfs) Use the cvmkfs command to initialize an Xsan volume based on the information in the volume’s configuration (in /Library/Filesystems/Xsan/config/volume.cfg). WARNING: Initializing a volume destroys all existing data on the volume. $ sudo cvmkfs [-G] [-F] [volume] Parameter Description -G Don’t display “Press return to continue” prompts -F Don’t display warning and verification prompts. Use this parameter with caution. volume The name of the volume to initialize.
To list files that are candidates for defragmentation: $ snfsdefrag -l [-D] [-v] [-K affinity] [-m count] [-r] target [target] [...] Parameter Description -c Display an extent count but don’t defragment target. -D Display debugging messages. -d Operate on files with other than the current depth. -e Report extents without defragmenting. -K affinity Only operate on files with the specified storage pool affinity.
Controlling the Xsan File System (xsanctl) Use the xsanctl command to control basic Xsan file system functions. For details, see the xsanctl man page. $ sudo xsanctl command xsanctl Commands xsanctl command Description ping Sends a “ping” message to the Xsan file system to verify that it’s responding to management requests. mount volume Mount an Xsan volume on the computer. volume – the name of the volume unmount volume Unmount an Xsan volume on the computer.
Viewing Logs The system log to which Xsan writes information about SANs is in /var/log/system.log. Volume logs are in /Library/Filesystems/Xsan/data/volume/log/cvlog, where volume is the name of the specific volume. Xsan Configuration Files Xsan stores its configuration information in the following files: Note: None of these files is intended to be edited by Xsan users, except under the direction of an Apple support engineer. File or folder in /Library/Filesystems/Xsan/config/ Contents volume.
Appendix B Using the Command Line
Glossary Glossary affinity A relationship between a folder on an Xsan volume and one or more storage pools that provide storage for the volume. The affinity guarantees that files placed in the folder are stored only on the associated storage pools. Storage pools can differ in capacity and performance, and affinities can be used to assure that data such as video, which requires high transfer speed, is stored on the fastest storage devices.
file system server See FSS. fill An Xsan storage pool allocation strategy. In a volume consisting of more than one storage pool, Xsan fills up the first pool before writing to the next. format (verb) In general, to prepare a disk for use by a particular file system. FSS File system server. The StorNext File System term for the computer that manages metadata in a storage area network (SAN). In Xsan, this is called a metadata controller. initialize To prepare a disk for use by a particular file system.
RAID Redundant Array of Independent (or Inexpensive) Disks. A grouping of multiple physical hard disks into a disk array, which either provides high-speed access to stored data, mirrors the data so that it can be rebuilt in case of disk failure, or both. The RAID array is presented to the storage system as a single logical storage unit. See also RAID array, RAID level. RAID 0 A RAID scheme in which data is distributed evenly in stripes across an array of drives.
stripe breadth An Xsan storage pool property. The number of bytes of data, expressed as a number of file system blocks, that Xsan writes to a LUN in a storage pool before moving to the next LUN in the pool. stripe group The StorNext File System term for an Xsan storage pool. volume A mountable allocation of storage that behaves, from the client’s perspective, like a local hard disk, hard disk partition, or network volume. In Xsan, a volume consists of one or more storage pools. See also logical disk.
A Index Index access permissions for folders 80 read-only volumes 82 unmounting a volume 81 access control list.
configuration requirements 24 monitoring connection failures 108 supported switches 24 files limit per volume 21 maximum size 21 name length limit 21 file systems. See volumes fill volume allocation strategy 63 firewall, and Xsan Admin 41 fragmentation 67 free space checking quota use 87 checking storage pool 104 checking volume 103 G grace period (quota) 86 graphs controller overall CPU use 104 controller overall IP network use 104 group ID.
R RAID schemes for LUNs 30 read-only volumes 82 refresh interval, Xsan Admin 41 repairing a volume 68 round robin volume allocation strategy 63 S SAN (storage area network) adding 52 adding clients 72 adding storage 53 managing multiple 52 moving clients 73, 74 name length limit 21 removing 52 renaming 51 security considerations 20, 30 serial number sending expiration notifications 105 Server Assistant 40 shared secret file 117 shell commands cvadmin 121 cvaffinity 124 cvcp 124 cvfsck 125 cvlabel 126 cvmkd
X Xsan Admin installing 51 remote SAN management 52 Xsan Admin application and firewalls 41 overview 41 preferences 41 140 Index refresh interval 41 xsanctl command 130 Xsan software compatibility with StorNext software 116 installing 45 removing (uninstalling) 83 version compatibility 10 Xsan User Quotas application 89
