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Understanding vSAN on-disk format versions and compatibility (2145267)

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This article outlines all vSAN on-disk format versions, including compatible features, interoperability and alternate version numbers.
vSAN has several different on-disk format versions available depending on the version and upgrade history of the cluster. Some on-disk format versions are transient while some are intended for long-term production. As certain vSAN features are tied to the on-disk format version, the format version must be accounted for when determining interoperability.


vSAN on-disk format versions are reported differently in some vSAN releases. As of vSAN 6.5, all on-disk format versions have been harmonized and the on-disk format version will be reported identically at all layers in the stack. In vSAN 6.2, however, the on-disk version may be reported differently in various levels of the stack. In vSAN 6.2, the on-disk format versions are reported as per the following table.

vSAN on-disk format version reporting

Version per vSphere Web Client Version per RVC *  Version per esxcli ** Version per CMMDS vSAN Release Notes
1 1 1 NA 5.5 ---
2 2 2 2 6.0-6.1 Format introduced with 6.0, includes performance and snapshot enhancements
2.5 2.5 2.5 3 6.2 Intermediate on-disk format to facilitate upgrade
3 3 3 4 6.2 Format introduced with 6.2, includes support for checksum, deduplication and compression
5 5 5 5 6.6 Format introduced with 6.6, includes support for encryption

  • * If RVC is an older version than vCenter, RVC will report the same as CMMDS.
  • ** ESXCLI does not report version information prior to vSAN 6.1.

vSAN Native on-disk format version

vSAN Release Native on-disk format version
5.5 1
6.0 2
6.1 2
6.2 4 *
6.5 4 *
6.6 5
Note: * On-disk format version 3 is an intermediate version. It is used briefly only during the upgrade process between on-disk format version 2 and on-disk format version 4.

vSAN on-disk format version support matrix

For interoperability, vSAN releases support the on-disk format versions of all prior releases,* and support is cumulative:

vSphere Version
On-disk format versions supported
1 2 4 5
5.5, Update 1+ X X X
6.0 GA
6.0 Update 1
6.0 Update 2
6.5 GA
"" denotes compatibility

: * When upgrading from vSAN 5.5, specific builds must be used to ensure backwards compatibility. For more information, see vSAN upgrade requirements (2145248).

Important: vSAN release interoperability is dictated by the on-disk format version. If any host in the cluster uses on-disk format version 2, for example, all hosts must use version 2 for cluster-wide compatibility until the applicable on-disk format upgrade has been completed. This is true even if some or all hosts in the cluster are capable of a higher on-disk format version. For more information about vSAN interoperability and upgrades, see VMware vSAN Upgrade Best Practices (2146381). To maintain compatibility, it make be necessary to format disks with an older on-disk format version. For more information, see How to format vSAN Disk Groups with a legacy format version (2146221).


vSAN on-disk format versions interoperability interop

See Also

Update History

04/21/2017 - Added vSAN 6.6 to Products

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