VMware Horizon

Solved! VMFS File Locking in VMware View 5.1 – All You Wanted to Know

By Fred Schimscheimer, Sr. Technical Marketing, End User Computing 

Ever wonder why VMware View would support more than eight hosts in an ESX cluster?

Wonder no more. VMware View 5.1 now supports up to 32 hosts in an ESX cluster!  That is provided a NFS data store is specified for linked clone replica creation.   Since more than eight hosts can now be used in an ESX cluster, VMware View 5.1 makes desktop consolidation even more efficient than ever before.

I recently reviewed a technical white paper that discusses VMFS File Locking and Its Impact in VMware View 5.1 and the number of hosts it can support in an ESX cluster.  It is a good read for those of you who want to understand the technical side of things.

You are given a primer on the VMFS File Locking mechanism, including:

  • Exclusive Lock
  • Read-Only Lock
  • Multi-Writer Lock
  • Eight vs 32 host limit in an ESX cluster

You’ll also discover that network attached storage (like NFS) is not affected by the eight host limit and that in View 5.1 you are able to select a cluster having more than eight hosts provided a NFS data store is used.   In addition, you’ll learn that NFS supports a protocol called Network Lock Manager (NLM) and that the Network Lock Manager uses an advisory locking scheme for locking.  It is this mechanism that allows View 5.1 to support up to 32 hosts.

Last but not least, this paper provides you with a few use cases and best practices that should be followed while using a large cluster (having more than eight hosts and using a NFS data store) in VMware View 5.1.  Take a look.  It is a good read.