Our recent exploits into SSD, hybrid storage (startup vendor) trials have provided me a renewed appreciation for the solid, staid, well QA'ed feature sets of the tier 1 storage vendors, in this case Netapp's DataMotion.
Datamotion is to the datastore as vMotion is to the VM.
Datamotion is "meta storage vMotion" and the benefits are analogous.
Our vSphere VMs run in vFiler NFS datastores on Netapp (Ontap 8.1) production cluster. We replicate our production cluster to our campus standby cluster. Just as vMotion allows for non-disruptive, zero downtime hypervisor upgrades, datamotion allows us to shift vFilers hosting dozens of VMs live, with zero downtime between physical clusters separated by campus/metro area distance.
We've employed datamotion for the last 3-4 cluster upgrades - "datamotion'ing" off all vFilers from the production cluster to the standby cluster, upgrading the evacuated cluster (Ontap versions, plus hardware, trays, flash cache SSD) - all with zero downtime.
In this age of storage startups - each with their own brand new filesystem which may or may not have your data integrity protected, I have to commend the engineering acumen behind datamotion. I have seen datamotions fail (< 5%) - but similar to when vMotions fail, this is prior to the cutover fail-safes and so its robust - no downtime - correct the previous issue and the next datamotion succeeds.
We recently installed Netapp SSD flash cache - in a follow up post I will use (unsupported online) datamotion between compare flash cache cluster heads to compare performance with and without the SSD.