@Mike_Laverick asked a question on twitter today about something that is stated in the Cloud Computing with vCloud Director book. His question was, and no he is not dyslectic he only had 140 characters 🙂
pg65. Order of storage tiers. Doesn’t that infer FC/SDD+VMFS is “race horse” and NFS “donkey”…???
Mike was referring to the following section in the book:
SLA | Service | Cost | RTO | Storage | RAID | Applications |
Tier 0 | Premium | $$$$$ | 20 min | SSD, FC | 1+0 | Exchange, SQL |
Tier 1 | Enterprise | $$$$ | 1 hour | FC | 1+0, 5 | Web servers, Sharepoint |
Tier 2 | Professional | $$$ | 2 hours | iSCSI, NFS | 3, 5, X | Custom apps, QA |
Tier 3 | Basic | $ | 2 days | NFS | 3, 5, X | Dev/Test |
This basically states, as Mike elegantly translated, that FC/SSD is top performing storage while NFS is slow or should I say “donkey”. Mike’s comment is completely fair. I don’t agree with this table and actually did recommend changing it, somehow that got lost during the editing phase. In the first place we shouldn’t have mixed protocols with disks. Even an FC array will perform crap if you have SATA spindles backing your VMFS volumes. Secondly, there is no way you could compare these really as there are so many factors to take in to account ranging from cache to raid-level to wire speed. I guess it is still an example as clearly mentioned on page 64, nevertheless it is misleading. I would personally prefer to have listed it as follows:
SLA | Service | Cost | RTO | Protocol | Disk | RAID | BC/DR |
Tier 1 | Enterprise | $$$ | 20 min | FC 8GBps | SSD | 10 | Sync replication |
Tier 2 | Professional | $$ | 1 hour | NFS 10GBps | FC 15k | 6 | Async Replication |
Tier 3 | Basic | $ | 1 day | iSCSI 1GBps | SATA 7k | 5 | Backup |
Of course with the side note that performance is not solely dictated by the transport mechanism used, there is no reason why NFS couldn’t or shouldn’t be Tier 1 to be honest. Once again this is just an example. Thanks Mike for pointing it out,