My ramblings on the stuff that holds it all together
Solid Sate SAN, Storage vMotion and VMWare – HSM for your VMs
You’ve been able to buy solid state SAN technology like the Tera-RAMSAN from TMS which gives you up to 1Tb of storage, presented over 4Gb/s fibre channel or Infiniband @10Gb/s… with the cost of flash storage dropping its going to soon fall in to the realms of affordability (from memory a year ago 1Tb SSD SAN was about £250k, so would assume that’s maybe £150k now – would be happy to see current pricing if anyone has it though).
If you were able to combine this with a set of ESX hosts dual-connected to the RAMSAN and traditional equipment (like an HP EVA or EMC Clariion) over a FC or iSCSI fabric then you could possibly leverage the new Storage vMotion features that are included in ESX 3.5 to achieve a 2nd level of performance and load levelling for a VM farm.
It’s pretty common knowledge that you can use vMotion and the DRS features to effectively load level or average VM CPU and memory load across a number of VMWare nodes within a cluster.
Using the infrastructure discussed above could add a second tier of load balancing without downtime to a DRS cluster. If a VM needs more disk throughput or is suffering from latency then you could move them to/from the more expensive solid-state storage tiers to FC-SCSI or even FATA disks, this ensures you are making the best use of fast, expensive storage vs. cheap, slow commodity storage.
Even if Virtual Center doesn’t have a native API for exposing this type of functionality or criteria for the DRS configuration you could leverage the plug-in or scripting architecture to use a manager of managers (or here) to map this across an enterprise and across multiple hypervisors (Sun, Xen, Hyper V)
I also see EMC integrating flash storage into the array itself, would be even better if you could transparently migrate LUNS to/from different arrays and disk storage without having to touch ESX at all.
Note: This is just a theory I’ve not actually tried this – but am hoping to get some eval kit and do a proof on concept…