From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: mke2fs stuck in D state while creating filesystem on md* Date: Tue, 18 Sep 2007 13:54:54 -0400 Message-ID: <46F010EE.3000202@tmr.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Wiesner Thomas Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Wiesner Thomas wrote: > Before running Linux software raid on a production system, I'm trying > to get the hang of it and use > 4 loopback devices on which I play with RAID5. > > I've: > * mdadm - v2.6.3 - 20th August 2007 > * mke2fs 1.37 (21-Mar-2005) Using EXT2FS Library version 1.37 > * Linux hazard 2.6.22.5 #2 PREEMPT Wed Aug 29 13:06:26 CEST 2007 > i686 GNU/Linux > > The HDD can transfer appriximately 40MB/s and the loopback files are > only 200 to 350MB. > > Well when I create a MD with > mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 > /dev/loop0 /dev/loop1 /dev/loop2 > and try to create the filesystem on it with > mke2fs /dev/md0 > mke2fs gets stuck in D state. Not always but sometimes. It hangs there > for different amounts of time, at least a > Minute or two. (Far longer than the filesystem creation process itself > takes.) Afterwards, the process continues and finishes. > Sometimes it hangs at 6/65 blocks, sometimes earlier, sometimes later, > but always quite early. > > The interesting line of a "ps ax" looks like: > 1609 tty2 D+ 0:00 mke2fs -j /dev/md0 > > It doesn't seem to be a real showstopper, but I think it's not a > normal behaviour. > While stuck, I don't see any CPU or disk activity. Trying to kill the > mke2fs seems to lead to > a completely stuck mke2fs (doesn't get out of D state) but I don't > know that for sure, because I did > that only once and didn't wait very long before I rebooted. > > The base System is a 3.1 (Sarge) with a plain Vanilla 2.6.22.5 kernel > and latest mdadm. > > If you need additional info or I should try something, I'm willing to > do that, because I've some time ATM. Has there been any progress on this? I think I saw it, or something similar, during some testing of recent 2.6.23-rc kernels, on mke2fs took about 11 min longer than all the others (~2 min) and it was not repeatable. I worry that process of more interest will have the same hang. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979