When creating a snapshot on virtual machine with virtual disks or virtual-mode Raw Device Mapping (RDM) disks, you experience these symptoms:
This failure occurs when the snapshot file at its maximum size is unable to fit into a datastore. Starting with ESX/ESXi 4.0 compare the maximum size of a snapshot redolog file with the maximum size of files on the datastore. The redolog file may not work correctly once it reaches the maximum size of the datastore. If the file could grow beyond the maximum size, ESX/ESXi cancels the Create Snapshot operation and displays this error instead.
Note: The above also applies to Virtual-mode Raw Device Mapping (RDM) disks (which you can also take snapshots of) attached to the virtual machine.
Compare the base disk size of the VMDK or virtual-mode RDM of the virtual machine against the block size of the datastore which contains the working directory of the virtual machine. By default, the working directory contains the virtual machine's .vmx configuration file. The maximum file size differs among versions of ESX/ESXi, and among versions of VMFS.
If you experience this error even after confirming that the snapshot files can fit on the datastore, proceed to the Calculating the overhead required by snapshot files.
ESXi 5.0 with VMFS5
On ESXi 5.0 and newly formatted VMFS5, a standard 1MB block size is available. The maximum file size is 2TB - 512Bytes.
Maximum File Size
2TB - 512Bytes
Note: On ESXi 5 hosts using VMFS5 upgraded from VMFS3, upgraded volumes inherit the VMFS3 block size. The default block size for new volumes is 1MB. The maximum file size, regardless of block size, is 2TB - 512Bytes. For more information, see theStorage Maximums table in Configuration Maximums for VMware vSphere 5.0.
ESX/ESXi 4.1 and ESXi 5.0 with VMFS3
On ESX/ESXi 4.1 and ESXi 5.0 using a VMFS3 datastore, the maximum file size corresponds to the block size of the VMFS datastore:
Maximum File Size
2TB - 512Bytes
ESX/ESXi 4.0 with VMFS3
On ESX/ESXi 4.0, the maximum file size corresponds to the block size of the VMFS3 datastore:
|Block Size||Maximum File Size|
|1MB||256GB - 512Bytes|
|2MB||512GB - 512Bytes|
|4MB||1TB - 512Bytes|
|8MB||2TB - 512Bytes|
To resolve this issue, either change the location of the virtual machine configuration files or change the
workingDir to a datastore with enough block size.
workingDir is the location where the snapshots are created, By default, the
workingDir contains the virtual machine's
.vmx configuration file. To change the
workingDir directory to a datastore with enough block size, see Creating snapshots in a different location than default virtual machine directory (1002929).
To move the virtual machine's disks and/or configuration files, use Storage vMotion or cold migration with relocation of files. For more information, see:
If the virtual machine already has snapshots, some procedures may not work or may try to create a snapshot. This table lists the requirements for the various procedures:
|Storage vMotion||The virtual machine must not have snapshots on ESX/ESXi 4.1 hosts or earlier. It may have snapshots on ESXi 5.0 or later.|
|Cold migration with relocation of files||The virtual machine may have snapshots. The source and destination hosts must be running ESX/ESXi 3.5 or later.|
|Change||The virtual machine may have snapshots. When new snapshots are created, new redologs are placed in the|
|Hot clone||The virtual machine may have snapshots, but the snapshot hierarchy must be less than 31 snapshots deep. Hot cloning a virtual machine creates a snapshot on the source at the beginning of the process, then deletes the snapshot at the end of the process.|
|Cold clone||The virtual machine may have snapshots. Cloning the virtual machine creates a new virtual machine with the same content as the original virtual machine, but without snapshots.|
|vMotion to ESX/ESXi 3.5||The virtual machine may have snapshots. The virtual machine must use hardware version 4. ESX/ESXi 3.5 does not perform the check described here and allows the creation of snapshots.|
|Maximum VMDK size||Maximum Overhead||Maximum size less overhead|
|256GB - 512B||~ 2GB||254GB|
|512GB - 512B||~ 4GB||508GB|
|1TB - 512B||~ 8GB||1016GB|
|2TB - 512B||~ 16GB||2032GB|
VMware recommends that you create virtual disks or virtual-mode RDMs that are smaller than the maximum size minus the overhead, to enable the use of features like snapshotting, cloning, and independent-nonpersistent disks.
Based on VMware KB 1012384