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

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Article ID: 340404

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

Symptoms: 

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

  • In the vSphere Client, you see entries similar to:

    Create virtual machine snapshot VIRTUALMACHINE File <unspecified filename> is larger than the maximum size supported by datastore '<unspecified 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 vmware.log file of the virtual machine, you see entries 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.

Environment

VMware vSphere ESXi 6.5
VMware vSphere ESXi 5.1
VMware vSphere ESXi 6.0
VMware vSphere ESXi 5.5

Cause

This issue occurs when the snapshot file at its maximum size plus the size of its required overhead is greater than the maximum file size allowed in the datastore containing the virtual machine. Starting with ESX/ESXi 4.0 you should compare the maximum size of a snapshot redolog file plus its required overhead with the maximum size of a file on the datastore. The redolog file may not work correctly once it exhausts all available space on the datastore. If the file and its overhead could grow beyond the maximum allowable file size for that datastore, ESX/ESXi cancels the Create Snapshot operation and displays the above error instead.

Note: This also applies to Virtual-mode Raw Device Mapping (RDM) disks (which you can also take snapshots of) attached to the virtual machine.

Additionally, For ESXi 5.0, 5.1, 5.5 and 6.0 (with VMFS3 or VMFS5 upgraded from VMFS3), this error occurs when any individual flat .vmdk file exceeds 2,181,843,386,368 bytes. Try to keep the size of the disk below 2032 GB for normal snapshot operations.

Note: This check does not occur on ESX/ESXi 3.5 and earlier versions. On these versions, a snapshot is created even if there is insufficient space to store a full-size redolog. In this case the virtual machine may enter an unrecoverable state.

Resolution

Maximum file size

The maximum size of a snapshot file is the size of the corresponding base disk and the size of the overhead required for that size of VMDK. If you examine the datastore which contains the working directory of the virtual machine, the VMFS volume containing it must by configuration allow a file of that size. By default, the working directory contains the virtual machine's .vmx configuration file. When created, the working directory VMDK may be configured at the maximum size (but see the recommendation below). The maximum file size differs among versions of ESX/ESXi, and among versions of VMFS, and according to the block size used in creating the datastore.

Before confirming that the snapshot files can fit on the datastore, proceed to the Calculating the overhead required by snapshot files section. Use this section to determine the overhead for the size snapshot file(s) you are creating. This varies as determined by the version of ESX/ESXi, the version of the datastore VMFS, and the block size used by the VMFS filesystem of that datastore. Next review the charts below to find the maximum allowable file size. The chart previously reviewed in Calculating the overhead shows the corresponding maximum file size less the overhead size. In general the space needed by a snapshot is the sum of the size of the base file VMDK and the size of the snapshot overhead required for each VMDK or RDM.
 
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 and 5.1 with VMFS5

On ESXi 5.0 and 5.1 with a newly formatted VMFS5, a standard 1MB block size is available.
 
Block Size
Maximum File Size
1MB
2TB - 512Bytes


Maximum file size and upgraded VMFS5 volumes

 

For ESXi 5.0 and later hosts using VMFS5 volumes upgraded from VMFS3, the upgraded volumes inherit the VMFS3 block size but the normal VMFS3 block size limits do not apply to the new upgraded VMFS5 volume. Here are the file size limits that apply to the different types of VMFS5 volumes.

 

  • For ESXi 5.0 and 5.1 the maximum file size, regardless of block size or VMFS volume upgrade state, is 2TB - 512Bytes.
  • For ESXi 5.5 and 6.x the maximum file size for a native (not upgraded) VMFS5 volume is 62TB. Virtual machines with files above the 2TB - 512Bytes size limit are not compatible with ESXi 5.1 and earlier. For more information about large VMDK support in vSphere 5.5, see Support for virtual machine disks larger than 2 TB in VMware ESXi 5.5 (2058287).
  • The default block size for new VMFS5 volumes created on an ESXi 5.5 or 6.0 host is 1MB.

 

For more information, see the Storage Maximums in: https://configmax.esp.vmware.com/home

For more details about the conditions and limitations of the increased file size compatibility in ESXi 5.5, see Support for virtual machine disks larger than 2 TB in vSphere 5.5 (2058287).
 

ESX/ESXi 4.1 and ESXi 5.x/6.0 with VMFS3

On ESX/ESXi 4.1 and ESXi 5.x./6.0 using a VMFS3 datastore, the maximum file size is determined by the block size of the VMFS3 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 is determined by the block size of the VMFS3 datastore:

Block Size Maximum File Size
1MB 256GB - 512Bytes
2MB 512GB - 512Bytes
4MB 1TB - 512Bytes
8MB 2TB - 512Bytes
 

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 size Maximum Overhead Maximum size less overhead
256GB - 512B ~ 2GB 254GB
512GB - 512B ~ 4GB 508GB
1TB - 512B ~ 8GB 1016GB
2TB - 512B ~ 16GB 2032GB

For example, a virtual machine has a 1024GB VMDK disk on an 8MB block Datastore but has the VMX and configuration files residing on a 4MB Block size Datastore. Both datastores may have a great deal of free space available, but an attempt to create a snapshot still fails with the "File is larger than maximum file size supported" error. The reason is that even though the Datastore containing the VMX file (assuming that is where the snapshots are being created) supports 1024GB file size it is not able to accommodate the overhead required (1024+8 = 1032GB). Freeing space on either Datastore have no effect.

Recommendation: VMware recommends that you create virtual disks or virtual-mode RDMs that are smaller than the total maximum snapshot sizes minus the corresponding overheads, to enable the use of features like taking snapshots, cloning, and independent-nonpersistent disks.
 
Note: With VMFS5, in ESXi 5.5 and later, no overhead calculations are required for virtual disks (VMDKs) greater than 2 TB in size, because during creation the system automatically accounts for the space required to snapshot the disk. With VMFS6, no overhead calculations are required for virtual disks (VMDKs) regardless of the size.
 

Methods to resolve this issue

To resolve this issue, either change the location of the virtual machine configuration files or change the workingDir to a datastore with enough space for the snapshot file(s).

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.

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:

Procedure Requirements
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 workingDir The virtual machine may have snapshots. When new snapshots are created, new redologs are placed in the workingDir directory.
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.
 

 



Additional Information

When performing a Storage vMotion migration, you may encounter this error:

Moving a virtual machine that has snapshots is not supported when the virtual machine has disks placed outside of its home datastore.

For more information on the maximum file size per VMFS block size, see the https://configmax.esp.vmware.com/home document for your version of ESX/ESXi.

 

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