Date: Wed, 27 Mar 2002 14:29:40 +0800 From: "Derek Barrett" <derekbarrett@graffiti.net> To: <dmiller@sparks.net>, "Kenneth D. Merry" <ken@kdm.org> Cc: freebsd-hardware@FreeBSD.ORG Subject: Re: RAID: Adaptec vs Mylex Message-ID: <20020327062940.9251.qmail@graffiti.net>
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I have no experience with Adaptec SCSI, but we chose the Adaptec 2400A (ATA) for a new box because of its friendly compatibility. FreeBSD instantly recognizes the card, and Adaptec has built native FreeBSD management utilities that will pretty painlessly install onto an X desktop. (Well sometimes the instructions are hard to find -- gotta look in the release notes, not the manual -- but once you find them, you can just add a package and run a setup script). One caveat with this card is that, if you chose RAID10, you can only have a stripe size of 64K. So for those of you running a database where you need a smaller block size, like 8 or 16, you would need to run RAID5, which is what we are running, even though we wanted RAID10. Though being a newbie to RAID10, I am thinking that having a smaller stripe size on RAID10 would negate its speed advantage anyway? Does anyone use a smaller stripe size on their RAID10 than 64K? ----- Original Message ----- From: David Miller <dmiller@sparks.net> Date: Tue, 26 Mar 2002 16:30:21 -0500 (EST) To: "Kenneth D. Merry" <ken@kdm.org> Subject: Re: RAID: Adaptec vs Mylex > On Tue, 26 Mar 2002, Kenneth D. Merry wrote: > > > On Tue, Mar 26, 2002 at 15:30:56 -0500, David Miller wrote: > > > Any input from real world users on the subject? I'm most interested in > > > the 3210S and 352. My use would be with RAID 10 support of a busy > > > database server doing zillions of writes/updates. Speed writing small > > > blocks is of the essence. > > > > > > Reliability, robustness, speed are critical factors. It will be hooked up > > > to 10 or 12 15K drives. > > > > > > Input? > > > > If you want a comparison of the two controllers: > > > > http://www.adaptec.com/worldwide/product/markeditorial.html?prodkey=3210_wp&type=Common&cat=%2fCommon%2fRAID+Upgrade > > Mylex has one on their site: (gawd frames are awful) > http://www.mylex.com/products/index.html -> competitive analysis -> > AcceleRAID 352 vs Adaptec 3200S (choose PDF). > > Naturally, it show the mylex adapter way out front. > > > > The only catch is that the comparison was done with RAID-5, not RAID-10. > > Unfortunately, that makes is pretty useless for me. > > > The two analysis look pretty far apart to start with, but when you look > at the details they may complement each other pretty well. Mylex wouldn't > call attention to it, of course, but area Adaptec beat it in pretty > thoroughly was with big blocks, espcecially with sequential IO and write > back enabled. > > That area is what the adaptec benchmark homes right in on, so they're not > in violent disagreement. > > Other differences were in the disk setup - adaptec used 8 drives on four > channels. Mylex used 18 drives on two channels. It may be that Mylex can > handle more total commands, but if you don't have enough drives it just > doesn't matter because the disks are the bottleneck. What I'm trying to > sort out is whether there would be any real world performance difference > to me in using either of them when updating 20 million 60 byte records in > a 160 million row table. > > > > So the read speed in the benchmarks above may be comparable to RAID-10, > > but the write speed for RAID-10 should be better. > > > > If you want high performance with lots of small chunks of data, I would > > recommend the Adaptec 5400S. It has a hardware parity engine that speeds > > up RAID-5 writes significantly. (If you're only doing RAID-10, though, it > > won't have any effect.) > > I think I really need the performance of raid 10. The database is small > enough that space efficiency is not an issue. Lots of little IO's - > mostly O's - are what really counts. Occasionally, handling directories > with 10K entries is an issue, so I'll probably want write-back enabled. > > > (disclaimer: I work for Adaptec.) > > Full disclosure, but not necessary around these parts. Your reputation > preceeds you Ken:) > > --- David > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hardware" in the body of the message > > -- _______________________________________________ Get your free email from http://www.graffiti.net Powered by Outblaze To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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