From mboxrd@z Thu Jan 1 00:00:00 1970 From: hpa@zytor.com (H. Peter Anvin) Subject: Re: EVMS or md? Date: Mon, 4 Apr 2005 22:15:49 +0000 (UTC) Message-ID: References: <200504040708.j3478bm03863@www.watkins-home.com> <1112642928.25469.28.camel@dyn95395156> <200504041446.50337.kewley@gps.caltech.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Followup to: <200504041446.50337.kewley@gps.caltech.edu> By author: David Kewley In newsgroup: linux.dev.raid > > Mike Tran wrote on Monday 04 April 2005 12:28: > > We (EVMS team) intended to support RAID6 last year. But as we all > > remember RAID6 was not stable then. I may write a plugin to support > > RAID6 soon. > > Hi Mike, > > In your view, is RAID6 now considered stable? How soon might you have an evms > plugin for it? ;) I'd love to use evms on my new filserver if it supported > RAID6. > I can't speak for the EVMS people, but I got to stress-test my RAID6 test system some this weekend; after having run in 1-disk degraded mode for several months (thus showing that the big bad "degraded write" bug has been thoroughly fixed) I changed the motherboard, and the kernel didn't support one of the controllers. And now there were 2 missing drives. Due to some bootloader problems, I ended up yo-yoing between the two kernels a bit more than I intended to, and went through quite a few RAID disk losses and rebuilds as a result. No hiccups, data losses, or missing functionality. At the end of the whole ordeal, the filesystem (1 TB, 50% full) was still quite prisine, and fsck confirmed this. I was quite pleased :) Oh, and doing the N-2 -> N-1 rebuild is slow (obviously), but not outrageously so. It rebuilt the 1 TB array in a matter of single-digit hours. CPU utilitization was quite high, obviously, but it didn't cripple the system by any means. -hpa