Re: [PERFORM] best arrangement of 3 disks for (insert) performance - Dell
The Dell PERC controllers have a very strong reputation for terrible performance. If you search the archives of the Dell Linux Power Edge list (dell.com/linux), you will find many, many people who get better performance from software RAID, rather than the hw RAID on the PERC. Having said that, the 3/SC might be one of the better PERC controllers. I would spend and hour or two and benchmark hw vs. sw before I committed to either one. Thom Dyson Director of Information Services Sybex, Inc. On 9/12/2003 9:55:40 AM, Richard Jones [EMAIL PROTECTED] wrote: The machine is coming from dell, and i have the option of a PERC 3/SC RAID Controller (32MB) or software raid. does anyone have any experience of this controller? its an additional £345 for this controller, i'd be interested to know what people think - my other option is to buy the raid controller separately, which appeals to me but i wouldnt know what to look for in a raid controller. that raid controller review site sounds like a good idea :) Richard. ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [PERFORM] best arrangement of 3 disks for (insert) performance - Dell
[EMAIL PROTECTED] (Thom Dyson) writes: The Dell PERC controllers have a very strong reputation for terrible performance. If you search the archives of the Dell Linux Power Edge list (dell.com/linux), you will find many, many people who get better performance from software RAID, rather than the hw RAID on the PERC. Having said that, the 3/SC might be one of the better PERC controllers. I would spend and hour or two and benchmark hw vs. sw before I committed to either one. I can't agree with that. 1. If you search the archives for messages dated a couple of years ago, you can find lots of messages indicating terrible performance. Drivers are not cast in concrete; there has been a LOT of change to them since then. 2. The second MAJOR merit to hardware RAID is the ability to hot-swap drives. Software RAID doesn't help with that at all. 3. The _immense_ performance improvement that can be gotten out of these controllers comes from having fsync() turn into a near no-op since changes can be committed to the 128K battery-backed cache REALLY QUICKLY. That is something you should avoid doing with software RAID in any case where you actually care about your data. That third part is where Big Wins come. It is the very same sort of big win from cacheing that we saw, years ago, when we improved system performance _immensely_ by adding a mere 16 bytes of cache by buying serial controller cards with cacheing UUARTs. It is akin to the way SCSI controllers got pretty big performance improvements by adding 256 bytes of tagged command cache. -- output = (cbbrowne @ libertyrms.info) http://dev6.int.libertyrms.com/ Christopher Browne (416) 646 3304 x124 (land) ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
