- Provisioning is a breeze
- You get the advantage of VMDK thin Provisioning since it's the default setting over NFS
- You can expand/decrease the NFS volume on the fly and realize the effect of the operation on the ESX server with the click of the datastore "refresh" button.
- You don't have to deal with VMFS or RDMs so you have no dilemma here
- No single disk I/O queue, so your performance is strictly dependent upon the size of the pipe and the disk array.
- You don't have to deal with FC switches, zones, HBAs, and identical LUN IDs across ESX servers
- You can restore (at least with NetApp you can), multiple VMs, individual VMs, or files within VMs.
- You can instantaneously clone (NetApp Flexclone), a single VM, or multiple VMs
- You can also backup whole VMs, or files within VMs
People may find this hard to believe, but the performance over NFS is actually better than FC or iSCSI not only in terms of throughtput but also in terms of latency. How can this be people ask? FC is 4Gb and Ethernet is 1Gb. I would say that this is a rather simplistic approach to performance. What folks don't realize is that:
- ESX server I/O is small block and extremely random which means that bandwidth matters little. IOs and response time matter a lot.
- You are not dealing with VMFS and a single managed disk I/O queue.
- You can have a Single mount point across multiple IP addesses
- You can use link aggregation IEEE 802.3ad (NetApp multimode VIF with IP aliases)
Given that server virtualization has incredible ramifications on storage in terms of storage capacity requirements, storage utilization and thus storage costs, I believe that the time where folks will warm up to NFS is closer than we think. With NFS you are thin provisioning by default and the VMDKs are thin as well. Plus any modification on the size of the NFS volume in terms of capacity is easily and immediately realized on the host side. Additionally, if you consider the fact that on average a VMFS volume is around 70-80% utilized (actually that maybe high) and the VMKD is around 70% you can easily conclude that your storage utilization is anywhere around from 49-56% excluding RAID overhead, then NFS starts to make a LOT of sense.
VMworld is next week and NetApp is a platinum sponsor. So, if you are attending, I would recommend you drop by Booth 701 and take a look at some incredibly exciting demos that have been put together showcasing the latest NetApp innovations with ESX server as well as VDI.
I'm hoping to be uploading the demo videos here next week or have links to them .