SAS 5ir raid card

[PaulGillespie]

Just wondering what people's opinions are of the SAS 5ir RAID cards. These are the cheaper raid cards that use a little CPU power and RAM probably to operate. They only support raid 1 and a max of 4 disks.

I have one in use on a PE840 but it's at a client's site so i can't play with it but the performance with 15k SAS disks is good for a 5 user network. I'm needing 3 new servers, again PE840s, to be used as SBS2003 servers with around 5 users per server. They will only have 2 hard disks in a raid 1 array. To upgrade to Perc cards will cost aroung £250 each so the SAS 5ir looks attractive.

Anyone used one in anger with SAS or SATA disks and had an array fail? how did the rebuild go?


Thanks

Paul

 

[technome]

Two cents, in my experience....
For raid 1, not raid 10 or raid 5, you get no benefit from the higher end raid adapters. A plain high end scsi adapter does as well with a 2 drive mirror. High end raid adapters, at least the affordable ones, act the same as SCSI adapters as to write and reads... data is written to one of the disks in a mirror set, then to the other. Reads are read from one of the disk in a mirror set, but NOT both. Once you go raid 10 or raid 5 on a high end raid adapter this changes, data is read from all disks involved at the same time due to the striping. As to writes in raid 10, there is a higher throughput than raid 1, also due to striping. On the low or high end adapters, the reads from, and writes to one of the drives in raid 1 is protection against corruption in the event of a drive failure.

You would not gain anything in raid 1 by laying out extra cash for the more expensive raid adapter, perhaps a small degree in reliability, as the manufacturer can afford to spend more on the components and testing. The higher end raid adapters also have far more releases of firmware and drivers which could affect some users in the long term, or if the user upgrades to different operating systems (except Adaptec raid, I stopped using them years ago, as the were late to release drivers, if any).


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[PaulGillespie]

Thanks Technome, that's kind of what i thought. I'd heard a bad report that these cards weren't very good at rebuilding a failed raid array! just wanted to hear from someone who'd had experience of this card if that was the case or not.

Cheers