It's a clustered file system, excellent support for sharing between ESX servers in a cluster.

Features:

• Allows access by multiple ESX Servers at the same time by implementing PROFILE locking. SCSI Reservations are only implemented when LUN meta DATA is updated (e.g. file name change, file size change, etc.)
• Add or delete an ESX Server from a VMware VMFS volume without disrupting other ESX Server hosts.
• LVM allows for adaptive block sizing and addressing for growing files allows you to increase a VMFS volume on the fly (by spanning multiple VMFS volumes) With ESX/ESXi 4 VMFS volumes also can be expanded using LUN expansion Optimize your virtual machine I/O with adjustable volume, disk, file and block sizes. Recover virtual MACHINES faster and more reliably in the event of server failure with Distributed journaling.

Limitations:

Can be shared with up to 32 ESX Servers. Can support LUNs with max size of 2TB and a max VMFS size of 64 TB as of version 4 (vSphere). "There is a VMFS3 limitation where each tree of linked CLONES can only be run on 8 ESX servers. For instance, if there is a tree of disks off the same base disk with 40 leaf nodes in the tree, all 40 leaf nodes can be simultaneously run but they can only run on up to 8 ESX hosts." VMFS3 limits files to 262,144 (218) blocks, which translates to 256 GB for 1 MB block sizes (the default) up to 2 TB for 8 MB block sizes.

It's a clustered file system, excellent support for sharing between ESX servers in a cluster.

Features:

Limitations:

Can be shared with up to 32 ESX Servers. Can support LUNs with max size of 2TB and a max VMFS size of 64 TB as of version 4 (vSphere). "There is a VMFS3 limitation where each tree of linked clones can only be run on 8 ESX servers. For instance, if there is a tree of disks off the same base disk with 40 leaf nodes in the tree, all 40 leaf nodes can be simultaneously run but they can only run on up to 8 ESX hosts." VMFS3 limits files to 262,144 (218) blocks, which translates to 256 GB for 1 MB block sizes (the default) up to 2 TB for 8 MB block sizes.