iSCSI benchmarking
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Does anybody have any benchmarking data or know where I can find out about SQL Server performance with iSCSI storage compared to local storage or Fiber channel SANs? Thanks
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I can't help you with the links but when we were looking at an iSCSI SAN and comparing with Fiber Channel we basically decided that iSCSI might be ok for a NAS (depending upon what you're using it for) but we were recommended to go down the fiber channel route for all database type requirements (even in dev and QA).
Most fiber channel connections now run at 2GB as opposed to a maximum of 1GB with the iSCSI, obviously you're never going to get the top speeds on either (around 60% max with ethernet) but for an extra couple of grand (sometimes the extra cost is much less depending on the deal you can get) the performance is going to be much better than an iSCSI based system.
Hope this helped
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If the storage is for databases the only choice is SAN. Database backups can exist on a NAS but there is a performance hit. For optimal performance on disk database and transaction log backups SAN is a clear winner.
RegardsRudy KomacsarSenior Database Administrator"Ave Caesar! - Morituri te salutamus."
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The folks on our database team know that SAN is the better choice and we've tried to express that to management but without some hard evidence we are fighting a losing battle. Management is convinced that iSCSI is the way to go but I think they are just looking at the cost savings of iSCSI and some salesman has done a good job of selling them on the idea of iSCSI
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It sounds as if they are being 'penny-wise' and 'pound-foolish'. Maybe digging on a strage vendor's website (EMC or Hitachi) for white papers might help. After all who is more expert on the subject ? If the whitepaper digging produces positive results and management still goes 'down the wrong path', well ...
RegardsRudy KomacsarSenior Database Administrator"Ave Caesar! - Morituri te salutamus."
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We had a couple of phone conferences with a few supliers when we were looking into the feasibility of iSCSI for our databases to live on.
Almost all of their storage experts told me the same thing, that Fiber is a much better choice than ethernet. Quite a few of the installations available require certain types of switches and they need setting up on a different subnet in order to prevent network storming. If your management don't mind the possibility of flooding their network (if it's not configured right) and having really crappy performance because of the delays introduced with iSCSI then I'd be looking for another job.
As I said earlier, we thought it was a really good idea, we looked into it, we changed our minds.
iSCSI has it's niche in the market place but as DB storage it's not up to the job.
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We are in the process of planning for a NetApp SAN in our firm. Our NetApp engineer gave us a rule of thumb for determining if a SQL server should use FibreChannel or iSCSI to connect to the Filer. If the total read/write activity to the disk is below 70 Mbit/second, then iSCSI (on a 1 Gbit network) should be able handle it. The real question for me is the stability of the iSCSI network connection. How reliable is it compared to a local disk? Right now, I do not have problems with suspect or corrupt databases, and I would not like invite these problems.
Cliff Norris
Database Administrator
Alston & Bird, LLP
Atlanta, Georgia
Cliff Norris
Database Administrator
Alston & Bird, LLP
Atlanta, GA
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