From mboxrd@z Thu Jan 1 00:00:00 1970 From: maarten van den Berg Subject: Re: Call for RAID-6 users Date: Fri, 30 Jul 2004 23:38:33 +0200 Sender: linux-raid-owner@vger.kernel.org Message-ID: <200407302338.33823.maarten@ultratux.net> References: <200407302311.04942.maarten@ultratux.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200407302311.04942.maarten@ultratux.net> Content-Disposition: inline To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Friday 30 July 2004 23:11, maarten van den Berg wrote: > On Saturday 24 July 2004 01:32, H. Peter Anvin wrote: > I'm still early in the testing phase, so nothing to report as yet. > But I have a question: I tried to reproduce a reported issue when creating > a degraded raid6 array. But when I created a raid6 array with one disk > missing, /proc/mdstat reported no resync going on. Am I not correct in > assuming that raid6 with 1 missing drive should at least start resyncing > the other drive(s) ? It would only be really degraded with two missing > drives... > > So instead, I defined a full raid6 array which it is now resyncing... > My resync speed is rather slow (6000K/sec). I'll have to compare it to > resyncing a raid5 array though before concluding anything from that. Cause > this system is somewhat CPU challenged indeed: a lowly celeron 500. To confirm, after stopping the raid6 array (didn't want to wait this long) I created a raid5 array on the same machine and it resyncs at 14000K/sec. Is this expected behaviour, the 6M/sec for raid6 vs 14M/sec for raid5 ? I suppose raid6 has to sync two drives, which would maybe explain the speed difference(?) In any case, hdparm -tT report 50M/sec on each single drive. Is this discrepancy in speed normal ? (yes yes, I played with the /proc/sys/dev/raid/ speed settings (to no avail)) Maarten -- When I answered where I wanted to go today, they just hung up -- Unknown