While I understand that this makes having local storage impossible, I believe there is a use case to have local storage in a shared storage datacenter. Consider the following: I have a few applications that require 1 milli second latency and at most 2 milli second. That is not consistenly achievable with shared storage, to that end I added flash storage to a few hypervisors. About 5% of my servers require this and are not that resource hungry to require a dedicated physical server. That same 5% also has no requirement to be migrated if a host fails.
I mentioned this in another thread already, please look into the VDSM scratchpad hook. It will allow you to attach (files on) the local SSDs (as disks) to VMs when those VMs start up. It will perfectly meet your use case if you only need to keep the data on the SSD while the VM is up. -- Barak Korren bkorren@redhat.com RHEV-CI Team