Does VCB snapshot include memory state

[dingding]

when i use VCB to backup a VM, it will create a snapshot. does this snapshot include the memory state? i know in vmware-cmd snapshot command, there is a option to include or exclude memory state.

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Idleness is not doing nothing. Idleness is being free to do anything.

[weinstein5]

I do not believe so since you will not be reverting back to that exact state -

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[macaal]

HI,

Have you an answer for your question ?

I'm on the same case, VCB take a snap memory or not ?

Thanks

[Lightbulb]

I do not believe so. With VCB full backup you basically get an enhanced crash consistent state. When you restore a windows VM you will offten get a warning that the last shutdown was unexpected, which can be ignored. This tend to indicate that what you get is a crash consistent restore point. I say enhanced because of the filesystem quiescence that is done prior to the snapshot.

[rubensluque]

Though the VCB does not save the memory state some applications like MS SQL Server supports the VSS (Volume Shadow Copy Service) Windows feature and can be safelly backuped. Because VSS will flush the logs before take the snapshot.

ps: VSS is suport by VCB 1.5

rgds,

[macaal]

Hello,

Thanks for your answer !

[macaal]

Hello,

Thanks a lot for you information

[Nick_F]

We find VCB often crashes our databases (inc. MS SQL 2005) during the snapshot so have reverted to LAN backups for those servers until the NetBackup DB agents are supported (probably v7 of NetBackup). Interesting if it works OK just running VCB scripts though as I didn't think NetBackup did much different.

[Erik_Zandboer]

It is all about VSS support. Via VSS your SQL server flushes data disk, then holds I/O. VSS returns that the system is ready to be snapshotted. VCB takes a snapshot. VSS tells SQL that it can continue I/O. The snapshot is then no longer crash consistent, and a restored VM should not go over the entire database for consistency.

Another way that works without VSS support (if your envirment allows for it), is to 1) power down the VM 2) create a snapshot 3) powerup the VM. This feature is incorporated in some full-image backup software (like esXpress for example). It is very solid, your VM will always be completely consistent, VSS support(ed) or not. The downside off course is, that your VM takes +-5 minutes of downtime every backup run....