So for those who didn’t know, ESXi 5.5 u1 had a pretty seveare issue relating to NFS.
So occasionally any connections to NFS storage would end up in an All Paths Down (APD) condition. This is obviously pretty poor as things tend to break when the storage is ripped out from underneath the VMs running on the hosts.
This has been a known bug by VMware. This issue had absolutely nothing to do with Network or Storage hardware, however NetApp had come out with a patch that would help prevent the issue.
In addition ESXi 5.5 was vulnerable to the Heartbleed issues. If you read that and are confused, well you must have lived under a rock.
VMware has released 5.5 U1b that has the patches baked in. If you don’t want to do a full update, the patch is here, http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2077361
A collegue of mine has create a script that you can run on your ESXi hosts to update the server if you don’t have VUM installed. You must enable SSH to the host.
# open firewall for outgoing http requests:
esxcli network firewall ruleset set -e true -r httpClient
# Install the ESXi 5.5 pre-U1 Heartbleed Fix Image Profile from the VMware Online depot
esxcli software profile update -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml -p ESXi-5.5.0-20140401020s-standard --allow-downgrades
# Reboot your host