Upgrading vCenter and ESXi Hosts 5.1 to 5.5 in a isilon environment

Hey all,

We have an ESXi cluster. All hosts are ESXi 5.1 and vCenter 5.1. We want to upgrade to ESXi 5.5 and upgrade vCenter to 5.5 as well.

The datastores are spanned across 4 isilon x400 NAS devices configured for NFS.  The version of OneFS currently running is 7.0.2.1

Has anyone successfully upgraded their vmware infrastrucutre in this or a similar environment?  Any caveats we should be looking for?  Any help is greatly appreciated!

Thanks and be well,

Carl