VMFS Accessibility

VMware ESX Server 2.1
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VMFS Accessibility

There are two modes for accessing VMFS volumes: public and shared.

public — This is the default mode for ESX Server.
With a public VMFS version 1 (VMFS-1) volume, multiple ESX Server computers have the ability to access the VMware ESX Server file system, as long as the VMFS volume is on a shared storage system (for example, a VMFS on a storage area network). However, only one ESX Server can access the VMFS volume at a time.
With a public VMFS version 2 (VMFS-2) volumes, multiple ESX Server computers can access the VMware ESX Server file system concurrently. VMware ESX Server file systems with a public mode have automatic locking to ensure file system consistency.
shared — Used for a VMFS volume that is used for failover-based clustering among virtual machines on the same or different ESX Servers.
For more information on clustering with ESX Server, see Configuration for Clustering.

Note: In ESX Server 2.1, private VMFS volumes are deprecated. If you have existing VMFS version 1 (VMFS-1) or VMFS version 2 (VMFS-2) private volumes, then you can continue to use them, but we recommend you change the access mode to public. There is no performance penalty in making this change.

VMFS Accessibility on a SAN

Any VMFS volume on a disk that is on a SAN should have VMFS accessibility set to public or shared. Public, the default and recommended accessibility mode, makes the VMFS volume available to multiple physical servers, and to the virtual machines on those servers. With VMFS-2 volumes, public access is concurrent to multiple physical servers, whereas for VMFS-1 volumes, public access is limited to a single server at a time. For more information on configuring ESX Server with a SAN, see Using Storage Area Networks with ESX Server.

Changing Storage Configuration Options

To create or modify disk partitions through the VMware Management Interface, complete the following steps.

Log in to the VMware Management Interface as root.
The Status Monitor page appears.
Click the Options tab.
Click Storage Configuration.
Make the appropriate changes, then click OK.
Note: You cannot change VMFS accessibility if there are any open files on the VMFS volume. (The attempted operation returns errors). Close any open files, then edit the VMFS volume.

See Configuring Storage: Disk Partitions and File Systems for additional information.

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