Simply put, it's flash acceleration. You install a VIB in ESXi and register the PernixData Management (virtual management appliance) plugin to vCenter. You can then take flash drives from each of your ESXi servers and clump them together to make a flash tier across all your hosts.
Does vSAN render it obsolete?:
Not really, it's a good solution to augment any existing SAN you might have. It also won't require much change. The scenery maybe changes as vSAN increases its configs max and traditional SANs fade, but that probably won't be for a long while.
The cool things:
- You can use any SSD you want. You don't have to purchase high-end or vendor specific SSD's.
- Reads and Writes can be accelerated.
- If the SSD fails, if configured, replicates that write to another SSD in the cluster.
- Yes, you would use network bandwidth @ this point only until the failed SSD is replaced.
- Most flash caching will only do reads because write redundancy can be somewhat problematic.
- If you use something like NetApps backup and recovery services, you don't have to replace it because you are not inherently changing anything.
- vSAN you would likely need to look @ a third-party or for small implementation VMware's backup solution.
- Assuming PernixData will support NFS in the future.
- Usable from ESXi 5.0
- vSAN requires 5.5 U1
This is a good in-between vSAN and standard monolithic SAN arrays. If you are using NFS, unfortunately, you are out of luck currently. Support for NFS is supposed to be on the way though.
You can find out more here: