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Creating a snapshot for a virtual machine fails with the error: File is larger than maximum file size supported

Symptoms

When creating a snapshot on virtual machine with virtual disks or virtual-mode Raw Device Mapping (RDM) disks, you experience these symptoms:

  • In the vSphere Client, you see one of the following errors:

    • Create virtual machine snapshot VIRTUALMACHINE File is larger than the maximum size supported by datastore ''
    • File is larger than the maximum size supported by datastore

  • In the hostd log file for ESX/ESXi 4.x, you see the error:

    Snapshot guest failed: The file is too big for the filesystem.

  • In the hostd log file for ESXi 5.0, you see the error:

    Failed to do snapshot op: Error: (21) The file is too big for the datastore. 

  • In the vmware.log file of the virtual machine, you see an error similar to:

    vmx| FILE: File_VMFSSupportsFileSize: Requested file size ( 554051831808) larger than maximum supported filesystem file size (274877906944)
    vmx| DiskLibCreateCustom: if your disk is on VMFS, you may consider increasing the block size.
    vmx| DISKLIB-LIB : Failed to create link: The destination file system does not support large files (12)
    vmx| SNAPSHOT: BranchDisk: Failed to create child disk ' /vmfs/volumes/uuid/vmname/vmname-000001.vmdk' : The destination file system does not support large files (12)
    vmx| SNAPSHOT: SnapshotBranch failed: The destination file system does not support large files (5).
    vmx| [msg.checkpoint.save.fail2.std3] Error encountered while saving snapshot.
    vmx| The destination file system does not support large files. 

Cause

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.

For ESXi 5.0, this error occurs when any individual flat .vmdk file exceeds 2,181,972,430,848 bytes. This is the size generated when adding a virtual disk with size of 1.984492366201720 TB is specified.
 
Note: This check does not occur on ESX/ESXi 3.5 and earlier. On these versions, a snapshot is created even if there is insufficient space to store a full-size redolog.

Resolution

Maximum file size

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.

Notes:
  • A virtual machine on NFS or VMFS has a maximum virtual disk size of 2TB - 512Bytes, the same as the maximum in each of these tables.
  • Virtual-mode RDM disks also have the above limitation as the snapshot process is the same.

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.

Block Size
Maximum File Size
1MB
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:

Block Size
Maximum File Size
1MB
256GB
2MB
512GB
4MB
1TB
8MB
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 SizeMaximum File Size
1MB256GB - 512Bytes
2MB512GB - 512Bytes
4MB1TB - 512Bytes
8MB2TB - 512Bytes

Moving files to accommodate space requirements

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.

The 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:

  • vSphere 5.0: Migrating Virtual Machines section of the vCenter Server and Host Management Guide.
  • vSphere 4.1: Migrating Virtual Machines section of the vSphere Datacenter Administration Guide.
  • vSphere 4.0: Migrating Virtual Machines section of the vSphere Basic System Administration gguide.

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:

ProcedureRequirements
Storage vMotionThe 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 filesThe virtual machine may have snapshots. The source and destination hosts must be running ESX/ESXi 3.5 or later.
ChangeworkingDirThe virtual machine may have snapshots. When new snapshots are created, new redologs are placed in theworkingDir directory.
Hot cloneThe 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 cloneThe 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 3.5The 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.

Calculating the overhead required by snapshot files

The failure depends on the size of the virtual disk. All virtual machines that have disks and virtual-mode RDMs greater than the maximum supported size by VMFS may experience this error. Overhead for the snapshot is approximately 2GB for a disk size of 256GB. If snapshots are to be used, consider the overhead while deciding the size of the disks:  

Maximum VMDK sizeMaximum OverheadMaximum size less overhead
256GB - 512B~ 2GB254GB
512GB - 512B~ 4GB508GB
1TB - 512B~ 8GB1016GB
2TB - 512B~ 16GB2032GB

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


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