We have a four-node ESX farm/cluster where each node is loaded with 512G of
physical memory. These ESX nodes are Cisco UCS blades. We are looking into
adding more memory to each of these ESX hosts to increase the footprint to
750G/node. One of the data center architects had informed us last year that per
Cisco, the sweet-spot of memory footprint on these blades is 512GB, after that
the memory access speed would drop from 1600MHZ to 1066MHZ (a drop of ~ 30%).
Because all of our VMs host application tiers and they run a lot of JVM
processes, we are concerned that a drop of 30% will negatively impact our
applications' performance. However, our data center has been telling us that
the drop will not be noticed by the application which I find hard to believe.
We also do not want to add another ESX host because of licensing cost.
I was wondering if anyone is running their ESX hosts with memory over 512G/host
and if they observed any issue with memory speed.
Thank you,
Amir
