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Volume creation and sizing
41 Dell EMC SC Series: Best Practices with VMware vSphere | 2060-M-BP-V
8.4 VMFS file systems and block sizes
Within ESXi, it is recommended to use VMFS-6, which is the recommended file system format selectable from
the vSphere client when creating a datastore.
8.4.1 VMFS-3
If there are any remaining VMFS-3 datastores in the environment, it is recommended they be retired, and
virtual machines be migrated to the latest-version VMFS-5/6 formatted datastore. As a best practice, create
new VMFS-5/6 datastores, and migrate virtual machines to them using Storage vMotion when possible.
Caution: Before upgrading a VMFS-3 datastore to VMFS-5, it is recommended that a snapshot is taken of
the datastore for protection against any possible loss of data.
8.4.2 VMFS-5
With VMFS-5, the default block size is 1 MB, and allows for up to a 64 TB datastore with up to a 62 TB
VMDK. This format is required for functionality such as the VAAI space reclamation primitive (SCSI UNMAP)
to reclaim storage after a VMDK is deleted. See section 16.3 for more information about VAAI.
8.4.3 VMFS-6
VMFS-6 shares many of the same configuration maximums as VMFS-5, however VMFS-6 allows for
automatic space reclamation (UNMAP) for thin provisioned volumes. Since there is no upgrade path from
VMFS-5 to VMFS-6, migration techniques such as Storage vMotion must be used to take advantage of the
new features.
With vSphere 7.0, VMFS-6 now supports SCSI-3 reservations allowing shared VMDKs for Windows Server
Failover Clustering (WSFC). For an overview, requirements, and caveats, see the VMware vSphere 7 Core
Storage whitepaper.