When Creating a snapshot for a virtual machine fails

Or you receive the error:
File is larger than the maximum size supported by datastore

Note: This error does not occur on ESX 3.5 or earlier.

ESX 4.0 is able to detect when a snapshot file at maximum size cannot fit into a datastore. Instead of allowing the file to be created, which may not work correctly if it grows to big, ESX cancels the operation and displays the above error.

To confirm if the snapshot files may be too big, compare the size of the virtual machine’s base disks against the block size of the datastore which contains the virtual machine’s working directory.

Note: If you are using Raw Device Map, you should compare the size of the RDMs instead of the base disks.

Read more…

To install vcb follow the instructions on this link.

The first time I came in contact with vcb I created some batch files to make vcb snapshots. I encountered all kind of problems. Snapshots that vcb didn’t remove. unexpected errors no vss support and some more issues.

To overcome some of these problems I created a vbs script vcbBackup.vbs. The full howto is comming soon for now only the code. Read more…

All snapshots are created in the default virtual machine directory. Even if the vmdk disk file is located on different datastore than the virtual machine, the delta files are created in the default virtual machine directory.

This article provides instructions to change the default location.

Changing the location of where the delta files are created is helpful if you need to:

• Create a snapshot but do not have enough space on the VMFS volume
• Power on a virtual machine but there is not enough space to create a swap file on the VMFS volume
  To change the default location:

1. Power off the virtual machine.
2. Add the following line to the VMX configuration file for the virtual machine:
   workingDir="<new_path_location>"
   For example:
   workingDir="/vmfs/volumes/46f1225f-552b0069-e03b-00145e808070/vm-snapshots"
3. To reload virtual machine configuration, run the command:
   # vimsh -ne "vmsvc/reload <VmId>"
   When you power on the virtual machine, snapshot files and VSWP files are created in the new location.

Note: If you do not want to redirect the virtual machine’s swap file, add the following line to the VMX configuration file, then reload the configuration:
sched.swap.dir="<path_to_vm_directory>"

When you power on the virtual machine, the swap file is created in the same directory as virtual machine.