From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Vitezslav T. Se'm" Subject: Re: How to build a big file server Date: Fri, 06 Jun 2003 13:16:35 +0200 Message-ID: <3EE07813.3000104@inway.cz> References: <1054800852.1997.15.camel@wusel.schnulli.de> <200306060143.13516.sam@vilain.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Sam Vilain Cc: Heinz-Josef Claes , reiserfs-list@namesys.com Hi. Sam Vilain wrote: >On Thu, 05 Jun 2003 20:14, Heinz-Josef Claes wrote: > > >>- I plan to build a system with IDE 250GB drives. 7 of them for raid 5 >>and one hot spare. The OS will be on separate hardware raid 1 on smaller >>disks. Does anybody have experience with IDE controlers for the big >>disks? Is it better to use hardware raid oder software raid >>(performance)? >> >> > >Yes, if massive disk space at virtually no cost is what you're after, >it has to be IDE. But, you don't have to give up the benefits of a >servicable data centre. Check out http://www.acme-technology.co.uk/ >for some fairly snazzy hot swap IDE rack mount enclosures, cases and >more. There must be other vendors out there, too. If you've got that >many disks, you NEED hot swap! > >As for the software RAID vs hardware RAID, my experience is that >software RAID 1 can deliver the same amount of disk space as hardware >RAID 5 for less total cost, factoring in the price of the RAID >controller. Of course, your storage density is worse for RAID 1, but >you could probably still fit your 10TB into a single rack, assuming >you can get 8 disks in a 3U chassis. RAID 1 in any form will *always* >outperform RAID 5, especially in the event of a failure. RAID 1 >arrays hardly notice, RAID 5 arrays slow to a crawl. > >btw, I wouldn't necessarily be too worried about stacking too many >devices on a single chain. Benchmark heavily all configurations with >a workload and close to the real workload of the device before buying >dozens of controllers, or settling on one plan recommended by some >self-professed `expert' trolling the reiserfs-list. Your bottleneck >may not be where you think. > This is not about performace mostly, but about reliability. When U have 2 disks on one ribon, there is a serious problem, when one of them crash, because in 99% cases, the other disk stops responding to. This is IDE, not SCSI. Travis >I'd also strongly suggest getting a motherboard with 64 bit and/or >66MHz PCI bus. The Tyan ThunderK7 is pretty good - a dual capable >Athlon board that's stable as hell, and you can run the OpenBIOS >project on it - manage your servers with a serial terminal server (eg, >a PC with a serial breakout card) instead of a dumbass KVM switch. > >Then, you'd have something that's almost as good as a commerical UNIX >platform, but not really. Personally, I'd get a quote for the arrays >running on Sparc hardware from http://www.anysystem.com/ (used Sun >parts peddlers) and offer that as a comparison. > >Running LVM to allocate a large RAID volume works exceedingly well >from a system administration standpoint, especially with reiserfs. >It's online resizing support is second to none > -- "Byval jsem krotitelem zvirat... Vetsinou tech nejnebezpecnejsich. - Krotitelem zvirat? Jo. Je to logicky pokracovani po tom, co jsem byl ucitelem... jenomze se nemusis starat o rodice."