From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Cizek Subject: Re: IBM xSeries stop responding during RAID1 reconstruction Date: Wed, 14 Jun 2006 10:46:09 -0500 Message-ID: <44902F41.8030300@rcn.com> References: <20060614085354.GA18106@rigacci.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20060614085354.GA18106@rigacci.org> Sender: linux-raid-owner@vger.kernel.org To: Niccolo Rigacci Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Niccolo Rigacci wrote: >Hi to all, > >I have a new IBM xSeries 206m with two SATA drives, I installed a >Debian Testing (Etch) and configured a software RAID as shown: > >Personalities : [raid1] >md1 : active raid1 sdb5[1] sda5[0] > 1951744 blocks [2/2] [UU] > >md2 : active raid1 sdb6[1] sda6[0] > 2931712 blocks [2/2] [UU] > >md3 : active raid1 sdb7[1] sda7[0] > 39061952 blocks [2/2] [UU] > >md0 : active raid1 sdb1[1] sda1[0] > 5855552 blocks [2/2] [UU] > >I experience this problem: whenever a volume is reconstructing >(syncing), the system stops responding. The machine is alive, >because it responds to the ping, the console is responsive but I >cannot pass the login prompt. It seems that every disk activity >is delayed and blocking. > >When the sync is complete, the machine start to respond again >perfectly. > >Any hints on how to start debugging? > > I ran into a similar problem using kernel 2.6.16.14 on an ASUS motherboard: When I mirrored two SATA drives it seemed to block all other disk I/O until the sync was complete. My symptoms were the same: all consoles were non-responsive and when I tried to login it just sat there until the sync was complete. I was able to work around this by lowering /proc/sys/dev/raid/speed_limit_max to a value below my disk thruput value (~ 50 MB/s) as follows: $ echo 45000 > /proc/sys/dev/raid/speed_limit_max That kept my system usable but didn't address the underlying problem of the raid resync not being appropriately throttled. I ended up configuring my system differently so this became a moot point for me. Hope this helps, Bill