Live Snapshots with writethrough disk image corrupts file system

[sherbang]

When using a writethrough disk image, if you take live snapshots and switch between them then the file system gets corrupted due to inconsistent information in the OS read/write caches.

It seems like VMs that use writethough disk images should not be able to create Live snapshots. If a user is using a filesystem that's capable of handling this, then they should be able to make the disk image multi-attach.

Alternatively, there should be a way to disable live snapshots at the VM level.

[sherbang]

This SuperUser post describes the same problem: ​http://superuser.com/questions/622093/corrupted-data-in-a-write-through-disk-using-a-live-snapshot-in-virtualbox

[Frank Mehnert]

The behavior of disk images attached in write-through mode is clearly documented in chapter 5.4 of the user manual. Write-through hard disks are completely unaffected by snapshots. And this is also mentioned all over the manual when snapshots are mentioned. As the write-through mode is not the default mode, the user should know what he is doing when he selects this mode. Therefore I don't think there is anything we can change here.