February 24, 2011
Unintentionally deleting a virtual disk
Have you ever lost a file that you certainly didn’t delete? Well that might happen with vmdk-files if datastore is not unpresented and virtual disk deleted in the right order.
Lets say that you have a virtual machine with two virtual disks in two different datastores; vmfs_a and vmfs_b. You then unpresent from ESX the LUN containing vmfs_b and vmdk-file of hard disk 2. After the LUN is unpresented the second virtual disk (which is still visible on vm’s settings) is pointing to the first virtual disk’s vmdk. So if you now remove the second virtual disk with the option ‘remove from virtual machine and delete files from disk’ it actually deletes the vmdk of the first virtual disk.
Vm with two virtual disks:
After unpresenting the datastore vmfs_b from ESX the second virtual disk’s disk file is pointing to the first virtual disk’s vmdk:
Removing ‘hard disk 2’ from vm with option ‘Remove from virtual machine and delete from disk’:
After removing the second virtual disk the first virtual disk still points to its original location:
When browsing to the vmfs_a datastore the test-vm.vmdk file is no longer there:
It’s this easy to unintentionally delete the wrong vmdk-file. So before unpresenting LUN from ESX make sure that the datastore is empty to avoid this kind of a situation. I would also suggest masking LUN before unpresenting it because all paths-down condition might occur when LUN is unpresented without masking.
VMware kb about all paths-down condition:
VMware kb about unpresenting LUN from ESX: