This is something I think might interest some of you, I’m going to do this next week actually as our new NetApp box is arriving.
Citrix announced XenServer Midnightride. I had a chance to try the ride this week. Before this new release, only normal snapshot is available at XenCenter GUI. It is now possible to create full VM snapshots including the disk and memory state. Virtual machines can be easily rolled back to prior snapshot states with a “revert to snapshot” option.
XenServer supports three types of VM snapshots: regular, quiesced and snapshot with memory. Regular snapshots are crash consistent and can be performed on all VM types. The VM snapshot contains all the storage information and VM configuration, including attached VIFs, allowing them to be exported and restored for backup purposes.
Quiesced snapshots take advantage of the Windows Volume Shadow Copy Service (VSS) to generate application consistent point-in-time snapshots. The VSS framework helps VSS-aware applications like Microsoft Exchange or Microsoft SQL Server to flush data to disk and prepare for the snapshot before it is taken. XenServer supports quiesced snapshots on Windows Server 2003 and Windows Server 2008 for both 32-bit and 64-bit variants. Windows 2000, Windows XP and Windows Vista are not supported.
Snapshot with memory save the VMs state (RAM).This can be useful if you are upgrading or patching software, or want to test a new application, but also want the option to be able to get back to the current, pre-change state (RAM) of the VM. Reverting back to a snapshot with memory, does not require a reboot of the VM.
The diagram below shows the three types of snapshots.
The diagram shows the snapshot tab of a VM, we can see a clear VM snapshot history. To revert a VM to “Snapshot (1) of Copy of Windows7”, simply right click on the snapshot and select “revert”.
Before a VM reverts to snapshot (1), an option of taking a snapshot of current stage is provided and snapshot (2) is taken and is branched off the “Now” – the current stage.
All the above features are based NetApp snapshot technology, the original and most functional point-in-time copy technology, enables you to protect your data with no performance impact and minimal consumption of storage space. Snapshot technology enables you to create point-in-time copies of file systems, which you can use to protect data—from a single file to a complete disaster recovery solution.
You can use this technology while applications are running and create a Snapshot copies in less than a second, regardless of volume size or level of activity on your NetApp system.