On July 10, VMware announced the release of
VMware vCenter Server 2.5 Update 5.
This update has one corrected issue for firewall communications between the ESX hosts and the
vCenter server. There also is one new feature for HA enabled clusters.
VMware HA is one of those features that I hate, love
and then hate again due to some rough patches with the feature in the second and third Updates.
vCenter Server Update 5 introduces support for higher consolidation on VMware HA-enabled clusters.
This allows the consolidation ratio to be up to 80 VMs per ESX host. One of the quiet points of this
update is that this is one of the only times I have ever seen VMware officially recommend an
increase to the service console RAM allocation. This new HA feature for VI3 has a few technical
configuration steps, outlined in this KB article. Among them is increasing the
service console RAM to 512 MB for ESX 3.5 hosts. For a variety of reasons, I provision the service
console RAM to 800 MB (the maximum) during host installations for ESX 3.5. During the installation,
I also provision the swap partition to be larger as well. It becomes an academic discussion about
the partition size for service console RAM changes made to an existing installation, but I always
provision the swap console to be larger than twice the service console maximum. Rich Bramley has good blog
post on partition provisioning over at VMETC.
What is not in the material is the distinction that comes with vSphere HA-enabled clusters, where
100 VMs are supported for hosts of up to 8 hosts per cluster. In HA-enabled clusters with 9 or more
hosts, the supported maximum number of VMs per host plummets to 40 VMs
per host (see an earlier post for this point).
This is incredibly relevant to me, as I consolidate at and above these numbers for VI3 and will be
getting on this quickly. If I have or hear of any issues with Update 5, I'll let you know here.
Likewise if an update to ESX 3 comes down the path, I'll cover that as well.
Posted by Rick Vanover on 07/14/2009 at 12:47 PM
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