Date: Wed, 1 Dec 1999 16:20:01 +0100 From: Brad Knowles <blk@skynet.be> To: David Gilbert <dgilbert@velocet.ca> Cc: David Gilbert <dgilbert@velocet.ca>, stable@FreeBSD.ORG Subject: Re: vinum experiences. Message-ID: <v0420550eb46aead415aa@[195.238.21.204]> In-Reply-To: <14405.12433.220410.215813@trooper.velocet.net> References: <14405.8810.777783.992833@trooper.velocet.net> <v04205508b46ad9a708dc@[195.238.21.204]> <14405.12433.220410.215813@trooper.velocet.net>
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At 9:28 AM -0500 1999/12/1, David Gilbert wrote: > Actually, I don't think this is a vinum problem. It appears that the > SCSI layer locks hard when a drive is missing, but I could be wrong. It is entirely possible that the problems you saw are with the cam SCSI driver locking up, but even if it didn't lock up, you'd also need support within vinum, otherwise it would do you no good. > Problem is that we have to program for this case... if it doesn't > work, then there's literally no point in vinum supporting RAID-5. Vinum is very much a work-in-progress. In fact, the RAID-5 part was only very recently publicly available (you used to have to write into another company, get a license approval from them, and then Greg could send you pre-compiled binaries). There's a lot of stuff within the RAID-5 implementation that continues to need work, and the whole failure/replacement process is a big part of that. > The big problem is that the barrier-to-entry in this experiement is a > few thousand $$, and people likely only get to work on it in the few > weeks between equipment arriving and equipment going into production. Hardware-wise, you can get controllers that support RAID-5, work under FreeBSD, and are not excessively expensive. However, their performance is likely to be less than desirable -- see <http://www.shub-internet.org/brad/FreeBSD/vinum.html>; for my personal experiences. At this stage, although vinum seems to work just fine for striping and mirroring (although you have to mirror the stripes, instead of being able to stripe the mirrors), it seems to have a number of open problems in the RAID-5 arena. Although I would (and do) use vinum for striping or mirroring on production servers, I would not yet choose to use vinum RAID-5 on a production server. -- These are my opinions -- not to be taken as official Skynet policy ____________________________________________________________________ |o| Brad Knowles, <blk@skynet.be> Belgacom Skynet NV/SA |o| |o| Systems Architect, News & FTP Admin Rue Col. Bourg, 124 |o| |o| Phone/Fax: +32-2-706.11.11/12.49 B-1140 Brussels |o| |o| http://www.skynet.be Belgium |o| \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ Unix is like a wigwam -- no Gates, no Windows, and an Apache inside. Unix is very user-friendly. It's just picky who its friends are. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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