How safe is suspending a VM?

[patrickds]

To have an UPS shutdown method that would work for all my clients (any brand of UPS) I'm writing a script to poweroff or suspend all running VMs and then shutdown the host (I'm actually borrowing parts from other scripts, to be truthful)

At this moment, I'm just left with one dilemma: how safe is suspending a VM in regards of application consistency?

There have been these problems with the use of the file system quiescing drivers corrupting databases and such, can suspending a VM cause the same problems or doesn't that apply?

Is there anything in the documentation about how exactly suspending is done, and what the possible risks to the VM are?

Patrick

[kjb007]

I find the suspend state to be a little different than a snapshot, but they are similar. The suspend will create its own set of state files, and will pause I/O to the disk, and write active memory to disk.

I've run into timing issues with suspended vm's. On an unsuspend, I've seen certain applications that are very time dependent have problems.

So, suspend comes with its own set of problems that are slightly different from a suspend, but how much they'll affect you will depend on how your application runs.

-KjB

[patrickds]

I guess I'll play it safe and stick to shutting down the VMs instead of suspending them.

Since the script will be used for all kinds of applications, i'd better not risk causing damage to clients data.