With ESXi 5.0 VMware now places the snapshot files in the directory that contains the .vmdk disk file and not the directory that contains the .vmx file as the previous versions of ESX(i) did in the past. With that being the case instead of just the datastore containing the .vmx file being filled up by open snapshots now any of the datastores containing a VM disk can get filled up by a open snapshot which can bring down a VM because one of the VMs datastore can't be updated.
The location of the snapshot files in ESXi 5 can fill up any of the datastores that contain a .vmdk file for a VM. Which in return can cause the the VM to go down and not be able to be powered back on.
When a datastore gets filled by an open snapshot, one way to correct the issue is to clone the disk and the disk can be attached to the VM that is having an issue because of an open snapshot. Please follow these steps to clone a disk from a filled up datastore.
1. Open the vSphere Client
2. Select the host that the VM resides on
3. Click on the Configuration Tab
4. Click on the Security Profile in the Software box
5. Click on Properties... on the Services Line under the Security Profile
6. Click on SSH
7. Click on Options
8. Click on Start
9. Find a datastore that has enough room for you to clone this disk to
10.Use application like putty to connect to the host that you enabled SSH on(can be downloaded from this link free of charge, http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
11.Once logged in use the following command to change to the datastore where the VM disk is going to be cloned to, "cd vmfs/volumes/newdatastore"
12.Once in the new datastore create a new directory for the VM diks to be cloned to by using the following command, "mkdir VMname"
13.Use the following command to change to the full datastore, "mkdir ../../fulldatastore/vmname"
14.From here use the following command to clone the disk, "vmkfstools -i vmname-00000x.vmdk ../../newdatastore/vmname/vmname.vmdk" (The VM should be powered off before the disk clone command is ran. 00000x.vmdk is the snapshot file that the VM is currently running on, this can be checked via the vSphere client by editing the VM and seeing what file the disk is currently pointing to.)
15.While the disk is cloning via the vSphere client edit the VM once again and remove the disk from the full datastore.(Remove from the virtual machine should be chosen)
16.Once the disk is removed, use the vSphere client to create a snapshot
17.Use the vSphere client to delete all snapshots via the snapshot manager
18.Once the disk is cloned edit the VM via the vSphere client and add the cloned disk to the VM
19.Power on the VM and it should not be fully operational
20.Once you have confirmed that the VM is all good and you no longer need the disk from the full datastore you can delete the disk via the Datastore browser
Please take a look at the following VMware KB for additional info about cloning a disk, http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1028042.
