PS Series Template Volumes and Thin Clones: How and When to Use Them Dell EMC Engineering November 2016 A Dell EMC Technical White Paper
Revisions Date Description February 2011 Initial release November 2016 Updated to reflect industry changes The information in this publication is provided “as is.” Dell Inc. makes no representations or warranties of any kind with respect to the information in this publication, and specifically disclaims implied warranties of merchantability or fitness for a particular purpose. Use, copying, and distribution of any software described in this publication requires an applicable software license.
Table of contents Revisions.............................................................................................................................................................................2 Executive summary.............................................................................................................................................................4 1 Introduction ......................................................................................................................
Executive summary This document shows how to configure Dell EMC PS Series template volumes and thin clones and discusses possible use cases including Microsoft® SQL Server®, Microsoft Hyper-V™, and VMware® vSphere®.
1 Introduction Data growth continues to increase exponentially and as result, technology companies are continually trying to develop new ways to reduce data storage consumption. In most cases, these technology developments are specific or are the best fit for certain applications. One example of these specific solutions is the use of template volumes and thin clones for Dell EMC PS Series arrays.
2 Configuring template volumes and thin clones Thin clones are sub-volumes of template volumes in which the template is a read-only version of volume at a specific point in time. Thin clones can be created from the template and are considered attached to the template volume but act as individual differencing disks that initially consume minimum volume reserve.
3 Use cases for template volumes and thin clones PS Series thin clones can be used in a number of ways, ranging from gold image deployments to object distribution. The simplest use for thin clones is to distribute like volume data to many locations or business units by creating copies from a template. This allows each location or business unit to use the data without multiplying out the space requirements.
Figure 1 shows the process flow to create database thin clones using the PS Series Auto-Snapshot Manager/Microsoft Edition (ASM/ME) and the PS Series Group Manager.
Now the database volumes can be converted to template volumes using the PS Series Group Manager GUI. 1. Select the smart copy used for the read-only copy of the database and locate the names of the volumes that were created in the properties window of ASM/ME shown in Figure 3.
2. Log into the PS Series Group Manager and locate the Smart Copy Clones in the Group Manager Volumes view. Select the smart copy clones, and using the Activities pane of Group Manager, select the Convert to template option shown in Figure 4. Locate volumes used for template volumes 3. Repeat this process for each clone volume in the database Smart Copy. 4. The volumes will be set offline and converted into template volumes.
5. Use ASM/ME to create thin clones of the created template database (see Figure 5).
3.3 Providing a powerful VMware test environment using thin clones Thin clones can bring huge value to a virtualized environment. In a VMware vSphere environment, all virtual machines are encapsulated into data files. These files allow the PS Series arrays, in combination with thin clones, to provide space-efficient copies of these environments allowing administrators to build out huge development and test farms.
1. Create new users for the developers: Developer1, Developer2, Developer3. 2. Create folders in vCenter to isolate the test environments: Developer1, Developer2, Developer3. 3. Create isolated vSwitches for the test environments to live on — Developer1, Developer2, Developer3 — and assign no physical NICs to them. When the test environments are created from the thin clone, the virtual NICs of the VMs will be associated with the vSwitch of the developer environment.
4. Assign users to folders. Different environments will have different permission structures, but in this example, each developer is only given permissions to their folder. This way, when a developer launches the vSphere client UI and logs in, as Developer1 for example, they will only see the folder and VMs that are in Developer1 folder and this will keep them segmented from the other developers.
1. Provision one thin clone as described in section 2. 2. Preform a rescan of the storage adapter from ESXi, and select Add Storage from the Storage tab. 3. When presented with the Mount Options dialogue shown in Figure 7, select Assign a new signature. Select the Assign new signature option 4. Once the datastore has been mounted and resignatured, it will have the same datastore label, but with snap- prefixed. Rename the datastore clone to a more suitable name, like Developer#. 5.
Note: Multiple snapshots can be mounted at once, however, this involves setting an advanced ESXi configuration setting that is now deprecated. Its use in a production environment is not recommended as a storage disruption while this setting is enabled, and can cause volumes to be resignatured. This can cause virtual machines to become unavailable.
Once each of the VMs is registered in the appropriate folder, you also need to change the network settings so that they are isolated. These are exact copies of the production VMs including hostname, MAC address, and IP address. Failure to isolate these VMs from the network can have severe implications. Select a VM and click Edit Properties. Click the Network Adapter and change the Network Label to one of the isolated vSwitches created earlier.
There are a variety of other things that can be done to these environments that are beyond the scope of this document, for example: Assign a second network adapter, assign new IP addresses to it, and have it residing on a reachable switch so that developers can remote into the environment or copy files across a network share. Take advantage of snapshots and allow developers to roll back their own test environments.
4 Summary PS Series template volumes and thin clones can be very valuable tools when applied in the right environments. They serve as space-efficient copies for environments that require high numbers of the same image on disk. These cases vary but can include test environments that change often and need to be reverted back to a base image, OS deployments, and data distribution. Whatever the case may be, template volumes and thin clones are an easy solution to meet challenging data-center needs.
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