From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Dan Williams" Subject: Re: is this raid5 OK ? Date: Thu, 29 Mar 2007 22:51:28 -0700 Message-ID: References: <237230840.20070329193857@kaneda.iguw.tuwien.ac.at> <17932.22575.558925.535963@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17932.22575.558925.535963@notabene.brown> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Rainer Fuegenstein , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 3/29/07, Neil Brown wrote: > On Thursday March 29, rfu@kaneda.iguw.tuwien.ac.at wrote: > > hi, > > > > I manually created my first raid5 on 4 400 GB pata harddisks: > > > > [root@server ~]# mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 --spare-devices=0 /dev/hde1 /dev/hdf1 /dev/hdg1 /dev/hdh1 > > mdadm: layout defaults to left-symmetric > > mdadm: chunk size defaults to 64K > > mdadm: size set to 390708736K > > mdadm: array /dev/md0 started. > > > > but, mdstat shows: > > > > [root@server ~]# cat /proc/mdstat > > Personalities : [raid6] [raid5] [raid4] > > md0 : active raid5 hdh1[4] hdg1[2] hdf1[1] hde1[0] > > 1172126208 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_] > > > > unused devices: > > > > I'm surprised to see that there's one "failed" device [UUU_] ? > > shouldn't it read [UUUU] ? > > It should read "UUU_" at first while building the 4th drive > (rebuilding a missing drive is faster that calculating and writing all > the parity blocks). But it doesn't seem to be doing that. > > What kernel version? Try the latest 2.6.x.y in that series. > I have seen something similar with older versions of mdadm when specifying all the member drives at once. Does the following kick things into action? mdadm --create /dev/md0 -n 4 -l 5 /dev/hd[efg]1 missing mdadm --add /dev/md0 /dev/hdh1 -- Dan