HP P4000 Remote Copy User Guide Abstract This guide provides information about configuring and using asynchronous replication of storage volumes and snapshots across geographic distances. For the latest version of this guide, see the HP website http://www.hp.com/support/manuals.
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Contents 1 Understanding and planning Remote Copy....................................................5 How Remote Copy works...........................................................................................................5 Graphical representations of Remote Copy..............................................................................5 Remote Copy and volume replication......................................................................................6 Uses for Remote Copy.................
Configuration for high availability........................................................................................32 How this configuration works for high availability...................................................................33 Best practices....................................................................................................................35 Achieving affordable disaster recovery.................................................................................
1 Understanding and planning Remote Copy Remote Copy provides a powerful and flexible method for reproducing data and keeping that replicated data available for disaster recovery, business continuance, backup and recovery, data migration, and data mining. How Remote Copy works Remote Copy uses the existing volume and snapshot features with replication across geographic distances to create remote snapshots.
Copying the primary snapshot to the remote snapshot When the primary snapshot is copying to the remote snapshot, the CMC depicts the process with a moving graphic of pages from the primary to the remote snapshot. The pages move in the direction of the data flow from primary to remote snapshot.
with asynchronous Remote Copy on a different cluster of storage systems creates a robust, high-availability configuration. Uses for Remote Copy Common uses for the Remote Copy application. Table 1 Uses for Remote Copy Use Remote Copy for How it works Business continuance and disaster recovery Remote Copy stores remote snapshots on a machine in a geographically separate location. The remote snapshots remain available in the event of a site or system failure at the primary site.
Table 2 Remote Copy, SAN/iQ, and storage systems Storage system level Remote Copy configuration Management groups • Create remote snapshots in the same management group or in a different management group than the primary volume. • If using different management groups, the remote bandwidth setting of the management group containing the remote volume determines the maximum rate of data transfer to the remote snapshot. • Event notification tells you when copies complete or fail.
Using schedules for Remote Copy Scheduled remote snapshots provide fault tolerance for business continuance and disaster recovery, and a consistent, predictable update of data for remote backup and recovery. Planning the Remote Copy schedule Planning is critical.
completed snapshots. Take the following characteristics of scheduled remote snapshots into account when planning retention policies. • The SAN/iQ software never deletes the last fully synchronized remote snapshot. Under some circumstances, such as unpredictable network speeds or varying snapshot size, a scheduled remote snapshot may create primary snapshots so frequently that the remote copy process cannot keep up with them.
Table 4 Scheduled Remote Copy planning checklist Configuration category Characteristic Scheduled snapshot Start time • Start date (mm/dd/yyyy) for the schedule to begin • Start time (mm:hh:ss) for the schedule to begin Recurrence • Recurrence is a yes or no choice.
2 Using Remote Copy For information about how Remote Copy works and how to plan capacity for Remote Copy, see “Understanding and planning remote copy” (page 5). Working with remote snapshots Remote snapshots are a core component of Remote Copy. Remote Copy uses the existing volume and snapshot capabilities to copy data across geographic distances. Application-managed snapshots—New for release 8.
If you selected a snapshot to start the process, you do not need to create a new snapshot. 2. (Optional) If you are using the Application Aware Snapshot Manager and want to quiesce the application before creating the snapshot, select Application-Managed Snapshot. The system fills in the Description field and and the snapshot inherits the server assignment of the volume. 3. Enter a name for the snapshot or accept the default.
Creating primary snapshots for volume sets When you create an application-managed snapshot of a volume in a volume set, the software recognizes that the volume is part of a volume set, and prompts you to create a snapshot for each volume in the volume set. The result is a snapshot set that corresponds to the volume set. To see any associated snapshots, select a snapshot, click the Details tab, and look at the Snapshot Set field.
IMPORTANT: group. All remote snapshots must be set up to use the same remote management 16. Click Update Pending Table Below to add this remote snapshot setup to the list at the bottom of the window. 17. Continue until each snapshot at the top of the window is set up. A green check mark shows the snapshot is set up. 18. Click Create Remote Copies. The remote copy of the primary snapshots to the remote volumes begins.
NOTE: There may be a delay in remote copy time. What the system does The system creates the remote snapshot in the cluster that contains the remote volume, and then copies the primary snapshot onto the remote snapshot. The process of copying the data may take some time. The remote snapshot appears below the remote volume in the navigation window when the copy completes.
5. 6. 7. 8. Copy the remote snapshot from the temporary PrimeSync management group to the existing remote Site B management group. Disassociate the temporary PrimeSync management group from the remote Site B management group. For more information, see “Disassociating remote management groups” (page 31). Delete the temporary PrimeSync management group.
Figure 5 Calculating a custom value for setting remote bandwidth Best practice Set the bandwidth speed the same in both directions unless you have an asymmetrical WAN link. To set the bandwidth: 1. In the navigation window, select either the remote or primary management group. 2. Click Management Group Tasks, and then select Edit Management Group. 3. Select the remote or primary management group. 4. Click Edit Remote Bandwidth. 5. Change the bandwidth setting as desired.
3. 4. Click Snapshot Tasks, and then select Delete Snapshot from the menu. Click OK. If the snapshot is not part of a snapshot set If the snapshot is part of a snapshot set A confirmation message opens. A warning message opens. • Click Delete Snapshot. • To delete all snapshots in the snapshot set, click Delete All Associated Snapshots. • To delete only the snapshot you selected, click Delete Selected Snapshot Only. • To cancel the deletion, click Cancel.
Figure 6 Viewing remote snapshot details During the remote copy process, the Remote Snapshot Details window reports current statistics. When the copy is completed, the statistics show summary data. For field descriptions, see “Fields for Remote Snapshot Details window” (page 20).
Table 5 Fields for Remote Snapshot Details window (continued) Statistic Fields Xs X. N/A signifies completed copies or in-progress copies not yet calculated. Est. Time Remaining The number of days, hours, minutes, and seconds estimated to remain in the copy process. The field format is Xd Xh Xm Xs X. N/A signifies completed copies or in-progress copies not yet calculated. Completion Time Time Zone date and time copy completed. The field format is MM/DD/YYYY HH:MM:SS [AM/PM].
Planning for scheduled remote snapshots is a crucial initial step in implementing Remote Copy. The following items require planning in advance for successful deployment of scheduled remote snapshots: • Recurrence (frequency) • Retention policies • Capacity planning • Timing For detailed information about these issues, see “Planning for Remote Copy” (page 7). Best practices for scheduling remote snapshots • Create a new remote volume to use with the scheduled remote snapshots.
Creating the schedule for volume sets When you create a schedule to remote snapshot a volume that has associated volumes, the system automatically creates remote snapshots for each associated volume. For information about volume sets, see the HP P4000 SAN Solution User Guide. The volume that you select when you create the schedule becomes the “owning” volume and the schedule displays (O) next to it. Check that the Volume Set box displays all of the volumes that you want to snapshot.
18. Click Update Pending Table Below to add this remote volume setup to the list at the bottom of the window. 19. Continue until each volume at the top of the window is set up. A green check mark shows the volume is set up. 20. Click Create Schedule. The timetable you just created is now listed in the Schedules tab view. What the system does If you created a new volume for the remote volume, the system creates a new primary snapshot of the primary volume and a remote snapshot of the remote volume.
Editing the schedule to remote snapshot a volume When editing the timetable for a schedule to remote snapshot a volume, you can change the following items: • Schedule—Description, start date and time, recurrence policy • Primary Setup—Retention policy • Remote Setup—Retention policy If the snapshot is part of a snapshot set, you can also verify that the volumes included in the schedule are the current volumes in the volume set.
and review the Snapshot Set field. For more information about volume sets and snapshot sets, see the HP P4000 SAN Solution User Guide. Using scripting for failover Application-based scripting provides the capability for creating, mounting, and deleting snapshots using scripts. Remote Copy can be scripted as well. Remote snapshots and scheduled remote snapshots can be created and managed using scripts.
Using failover to remote volume If the primary volume is not available, you can use the wizard to promote the remote volume to an acting primary volume. 1. In the navigation view, select the volume to convert. 2. Right-click the volume, and then select Failover/Failback Volume. 3. Click Next. 4. Select the reason you are failing over the volume. Use the second choice if your primary volume is not available and you want to get an acting primary volume into production. 5.
Table 6 Timeline of failover (continued) Time Event What happens 1:33 p.m. Scripted failover causes remote volume ActPrimaryVol_1 becomes primary to become the acting primary volume. and active, and usable to application server. 2:00 p.m. Original primary volume comes back OrigPrimaryVol_1 is online. online. The following data needs to be synchronized once the primary volume is back online: • Original volume, which contains data from 1:00 to 1:30 p.m.
1. 2. 3. 4. 5. Stop the application that is accessing the acting primary volume. Create a remote snapshot of the acting primary volume. As your target, create a remote volume, which will later be converted into your primary volume. Convert the remote volume into a primary volume. Make the acting primary volume into the remote volume. This creates a snapshot of that volume. 6. 7. Configure a new timetable for the scheduled remote snapshots on the new primary volume.
3. 4. Review the snapshot Details tab to ensure you have selected the correct snapshot. Click Snapshot Tasks on Details tab, and then select Roll Back Volume. Figure 8 Rolling back a primary volume if iSCSI sessions are still connected Figure 9 Rolling back a primary volume if iSCSI sessions are not connected 5. 6. Log off any connected iSCSI sessions. Click OK. The primary snapshot version of the primary volume is restored as a volume with the same name. 7.
New for release 8.0 Consider using the SmartClone feature to create a split mirror. The SmartClone volume is an exact copy of the volume or snapshot yet consumes no extra space on the SAN. Creating a split mirror To create a split mirror: • Create a remote snapshot. • Create a server for client access. • Configure clients to access the remote snapshot. Disassociating remote management groups Management groups become associated when linked by either remote snapshots or scheduled remote snapshots.
3 Sample Remote Copy configurations Because of its flexibility, Remote Copy is useful in a variety of configurations. The sample configurations described in this chapter show only a few ways to use Remote Copy for business continuance, backup and recovery, data migration, and data mining. Using Remote Copy for business continuance Business continuance is composed of disaster recovery and high availability of data.
Figure 10 High availability example configuration How this configuration works for high availability If the production application server or volumes become unavailable, application processing fails over to the backup application server. The remote volume and remote snapshots become acting primary, and the backup application server becomes the acting production application server, accessing data from the acting primary volume.
Failover to the backup application server To maintain availability of the applications and the remaining data, the following process occurs: 1. A script or other application monitoring the production application server discovers that the primary volume is not available. A script executes to fail over to the backup application server. 2. The backup application server executes a script to convert the remote volume into a primary volume so that the volume can be accessed by the backup application server.
Best practices Remote snapshots with volume replication Use remote snapshots in conjunction with local, synchronous volume replication, known as Network RAID. Using remote snapshots alone, any data written to the primary volume since the most recent remote snapshot was created will be unavailable if the primary volume is unavailable. However, you can lessen the impact of primary volume failure by using Network RAID.
Figure 13 High availability during failover-Example configuration Achieving affordable disaster recovery Even if you do not have clustered application servers or network bandwidth required for configuring hot backup sites, you can still use Remote Copy to protect your data during an emergency. Using remote snapshots, you can maintain copies of your volumes in remote sites.
Figure 14 Affordable disaster recovery example configuration How this works for affordable disaster recovery If the storage systems in your primary location fail or volumes become unavailable, the off-site location contains the most recent remote snapshots. • Use the remote snapshots to resume operations as shown in “Restoring from a remote volume” (page 38). If you created tape backups, you can recover data from tape backups, as shown in “Restoring from tape backup” (page 38).
2. Configure application servers to access the primary volume, or if network connections are not fast enough to facilitate reading and writing to the off-site location, copy this volume to a location where application servers can access it more efficiently. Figure 15 Restoring from a remote volume In “Restoring from a remote volume” (page 38) note the volume labeled Primary Snapshot in the Production Site. It originated as a read only backup, but is brought into use as an acting primary.
Best practices Select an optimum recurrence schedule. Select a recurrence schedule for remote snapshots that minimizes the potential for data loss. Any data written to the primary volume since the most recent remote snapshot was created will be unavailable if the primary volume is unavailable. Consider how much data you are willing to lose in the event of an emergency and set the recurrence for creating remote snapshots accordingly.
Configuration for off-site backup and recovery To use remote snapshots for off-site tape backup, create remote snapshots for access by your tape backup application: • Create remote volumes in your backup location. • Configure your backup application to access the remote snapshots. • Configure schedules to create remote snapshots in the designated off-site locations.
NOTE: Retention of snapshots affects the amount of space that is used in the cluster of storage systems. Balance the number of snapshots to retain with the amount of space you are willing to use. You can still access remote snapshots or tape backups if you want to roll back to a snapshot that you did not retain. • Retain remote snapshots in the backup location to facilitate fast recovery of backed-up data.
Figure 18 nondestructive rollback example How this configuration works for nondestructive rollback You can choose to roll back either the primary snapshot or the remote snapshot. Rolling back one of the snapshots requires that you delete more recent snapshots of that volume. The other volume retains the full set of snapshots. You can continue to make snapshots even though one side was rolled back and the other side was not.
Figure 19 nondestructive rollback from the primary snapshot • To roll back the remote snapshot, you must first make the remote volume into a primary volume. This stops scheduled creation of remote snapshots, which may jeopardize your high availability, disaster recovery, or routine backup strategies. “nondestructive rollback from the remote snapshot” (page 44) shows rollback of the remote snapshot.
Figure 20 nondestructive rollback from the remote snapshot Best practices Roll back the primary snapshot and keep the remote snapshots as a backup. To ensure that Remote Copy continues to operate, roll back the primary volume as follows: 1. Preserve the current state of the primary volume that you want to roll back by creating a one-time (manual) remote snapshot of it. 2. Roll back the volume. Before roll back, scheduled remote snapshots fail.
Configuration for data migration To make a copy of a volume in a remote location, configure a cluster of storage systems in the remote location with enough space to accommodate the volume. See “Data migration example configuration” (page 45) for an example configuration. Figure 21 Data migration example configuration How this configuration works for data migration Suppose you want to create a complete copy of a volume for an application to use in a different location. 1.
Figure 22 Configuration after data migration 46 Sample Remote Copy configurations
4 Support and other resources Contacting HP For worldwide technical support information, see the HP support website: http://www.hp.
New and changed information in this edition The following additions and changes have been made for this edition: • The following information has been updated: ◦ P4000 SAN Solution software and user manuals have been rebranded ◦ Additional functionality has been added for quiescing application servers before taking snapshots on both Windows servers and VMware servers.
Glossary The following glossary provides definitions of terms used in the SAN/iQ software and the HP P4000 SAN Solution. acting primary volume The remote volume, when it assumes the role of the primary volume in a failover scenario. Active-Passive A type of network bonding which, in the event of a NIC failure, causes the logical interface to use another NIC in the bond until the preferred NIC resumes operation. At that point, data transfer resumes on the preferred NIC.
DSM Device Specific Module. DSM for MPIO The HP P4000 DSM for MPIO vendor-specific DSM that interfaces with the Microsoft MPIO framework. failback After failover, the process by which you restore the primary volume and turn the acting primary back into a remote volume. failover The process by which the user transfers operation of the application server over to the remote volume. This can be a manual operation, a scripted operation, or VMware enabled.
Multi-Site cluster A cluster of storage that spans multiple sites (up to three). A Multi-Site cluster must meet at least one of the following conditions: • Contain storage systems that reside in two or more sites • Contain storage systems that span subnets • Contain multiple VIPs. The cluster can have a single site, and the multiple VIPs make it a multi-site cluster. network RAID Synchronous replication, mirroring or parity protection on a volume-by-volume basis.
RAID status Condition of RAID on the storage system: • Normal - RAID is synchronized and running. No action is required. • Rebuild - A new disk has been inserted in a drive bay and RAID is currently rebuilding. No action is required. • Degraded - RAID is not functioning properly. Either a disk needs to be replaced or a replacement disk has been inserted in a drive. • Off - Data cannot be stored on the storage system. The storage system is offline and flashes red in the network window.
shared snapshot Shared snapshots occur when a clone point is created from a newer snapshot that has older snapshots below it in the tree. All the volumes created from the clone point will display these older snapshots that they share, as well as the clone point. site A user-designated location in which storage systems are installed. Multi-Site SAN configurations have multiple sites with storage systems in each site, and each site has its own subnet.
volume set Two or more volumes used by an application. For example, you may set up Exchange to use two volumes to support a StorageGroup: one for mailbox data and one for logs. Those two volumes make a volume set. volume size The size of the virtual device communicated to the operating system and the applications. VSS Provider HP P4000 VSS Provider is the hardware provider that supports the Volume Shadow Copy Service on the HP P4000 SAN Solution.
Index A adding a remote snapshot schedule, 21 a remote volume, 15 remote snapshots, 12 affordable disaster recovery best practices, 39 configuration, 36 application-managed snapshots creating, 13, 22, 23 creating primary snapshot for volume sets, 14, 23 deleting remote, 18 failing over from, 25 promoting remote to primary, 27 rolling back from, 29, 30 B backup and recovery using Remote Copy, 39 benefits of Remote Copy, 7 best practices for affordable disaster recovery, 39 for high availability, 35 for nond
and Remote Copy, 35 best practices, 35 configuration diagram, 32 configuration for, 32 configuration of Remote Copy, 35 HP technical support, 47 I icons for Remote Copy, 5 Insight Remote Support software, 47 M management groups disassociating, 31 disassociating PrimeSync, 17 temporary, for PrimeSync, 16 merging data for failback, 34 monitoring progress of remote copy, 21 remote copy details, 19 remote snapshots, 19 N Network RAID and Remote Copy, 7 nondestructive rollback best practices, 44 configuration
creating application-managed, 13, 22, 23 creating application-managed for volume sets, 14, 23 deleting schedules, 24 pausing or resuming, 24 scheduling, 22 split mirrors, creating, 30 Subscriber's Choice, HP, 47 support software, remote, 47 synchronizing data after failover, 27 after failover, between acting primary volumes and original primary volumes, 28 T technical support HP, 47 service locator website, 48 timeline of failover, 27 U uses for Remote Copy, 7 using Remote Copy for business continuance, 3
