Hyper-V equivalent to VMware non-persistent drives?

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Psychor

Limp Gawd
Joined
Dec 22, 2007
Messages
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In VMware you could set up a drive and OS and then lock down the drive so that all changes to the VM were lost when the VM was shut down. This was great and provided a great test environment. Is there a way to do this in Hyper-V? I could not find one.

Thank you.
 
There is a hyper-v feature called snapshots. However, I have not used it before. Here is a blog explaining the process, which I'm fairly certain is similar to what you are looking for.

http://blogs.msdn.com/b/virtual_pc_guy/archive/2008/01/16/managing-snapshots-with-hyper-v.aspx

Hyper-V introduces the concept of virtual machine snapshots - which is to say point in time images of a virtual machine that you can return to at any stage. These snapshots are implemented in the virtualization layer - and can be taken at any time with any guest operating system (even during an operating system installation). Snapshots can be taken whether the virtual machine is running or stopped. If the virtual machine is running when the snapshot is taken there is no downtime involved to create the snapshot.
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Snapshots are just like any other snapshot. A backup in time. Not much of a difference in VMware or Hyper-V. VMware called disks that lose their changes on reboot "undoable". Looks like its deprecated now at least in ESXi. It may still exist in VMware Workstation.

http://www.vmware.com/support/developer/PowerCLI/PowerCLI41/html/New-HardDisk.html

PersistenceSpecify the disk persistence mode. The valid values are Persistent, NonPersistent, IndependentPersistent, IndependentNonPersistent, and Undoable. This parameter is supported only when the disk type is set to ?rawVirtual? or ?flat?. The 'NonPersistent' and 'Undoable' persistence policies are deprecated and will be disabled in a future release. Their usage is not recommended because they do not work with snapshots and are not supported on ESX 3.5 and higher.
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QHalo said:
Snapshots are just like any other snapshot. A backup in time. Not much of a difference in VMware or Hyper-V. VMware called disks that lose their changes on reboot "undoable". Looks like its deprecated now at least in ESXi. It may still exist in VMware Workstation.

http://www.vmware.com/support/developer/PowerCLI/PowerCLI41/html/New-HardDisk.html
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Be careful with terms - they're NOT a backup in time. They're a redo log of all events and changes on the hard drives from the moment you hit "snapshot", as well as potentially a copy of the RAM at time of snapshot. They're VERY different from LUN snapshots or native snapshots in other operating systems. The snapshot itself relies on having all the original files to be functional - the deltas are just COW files for changes.

Disks that lose changes on reboot are called independent non-persistent, and it's in all versions of ESX from 2.5 on - still fully in ESX5.
 
lopoetve said:
Be careful with terms - they're NOT a backup in time. They're a redo log of all events and changes on the hard drives from the moment you hit "snapshot", as well as potentially a copy of the RAM at time of snapshot. They're VERY different from LUN snapshots or native snapshots in other operating systems. The snapshot itself relies on having all the original files to be functional - the deltas are just COW files for changes.

Disks that lose changes on reboot are called independent non-persistent, and it's in all versions of ESX from 2.5 on - still fully in ESX5.
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I stand corrected.
 
lopoetve said:
Set your drives to independent non-persistent. All changes will be discarded (from a redo log) when you shut the VM down.
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Yes, with VMware I could do this and have done this. I'm wondering how to do such with Hyper-V. Thanks.
 
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