raid1: resync hanging until reboot

raid1: resync hanging until reboot

[Alfred Isele]

Hello!

When we disable a partition from a raid meta device
and try to reattach it again without a reboot in between
the resynch often starts hanging. After a reboot the
resynch does complete. In detail:

We use Linux version 2.4.19-64GB-SMP 

We create a raid1 meta devivce:

    mdadm -Cv /dev/md0 -l1 -n2 /dev/sda1 /dev/sdb1

We disable one piece from the meta device:

    mdadm /dev/md0 -f /dev/sda1 -r /dev/sda1

We reattach it to the meta device:

	mdadm /dev/md0 -a /dev/sda1

And very often but not always the resych hangs with
cat /proc/mdstat showing:

	md0 : active raid1 sda1[2] sdb1[1]
      	80256 blocks [2/1] [_U]
      	[>....................]  recovery =  0.0% (0/80256) finish=26.7min
speed=0K/sec


Does anybody know a solution to this problem?
Thank you very much
Alfred	

RE: raid1: resync hanging until reboot

[Cress, Andrew R]

I've seen something similar in 2.4.18, and here's how we patched it.
http://scsirastools.sourceforge.net/kern/2.4.18/raid_resync.patch
It's short, so I've also included it below, but the formatting of the email
may wrap some lines.

Andy Cress

--- linux-2.4.18/drivers/md/md.c.orig	Thu Jan 30 10:35:01 2003
+++ linux-2.4.18/drivers/md/md.c	Thu Jan 30 10:37:13 2003
@@ -3424,6 +3424,10 @@
 	wake_up(&mddev->recovery_wait);
 	if (!ok) {
 		// stop recovery, signal do_sync ....
+		if (mddev->pers->stop_resync)
+			mddev->pers->stop_resync(mddev);
+		if (mddev->recovery_running)
+			md_interrupt_thread(md_recovery_thread);
 	}
 }
 
@@ -3578,7 +3582,7 @@
 	 * this also signals 'finished resyncing' to md_stop
 	 */
 out:
-	wait_event(mddev->recovery_wait,
atomic_read(&mddev->recovery_active)==0);
+	wait_disk_event(mddev->recovery_wait,
atomic_read(&mddev->recovery_active)==0);
 	up(&mddev->resync_sem);
 out_nolock:
 	mddev->curr_resync = 0;

-----Original Message-----
From: Alfred Isele [mailto:Alfred.Isele@fujitsu-siemens.com] 
Sent: Monday, April 07, 2003 9:25 AM
To: linux-raid@vger.kernel.org
Subject: raid1: resync hanging until reboot



Hello!

When we disable a partition from a raid meta device
and try to reattach it again without a reboot in between
the resynch often starts hanging. After a reboot the
resynch does complete. In detail:

We use Linux version 2.4.19-64GB-SMP 

We create a raid1 meta devivce:

    mdadm -Cv /dev/md0 -l1 -n2 /dev/sda1 /dev/sdb1

We disable one piece from the meta device:

    mdadm /dev/md0 -f /dev/sda1 -r /dev/sda1

We reattach it to the meta device:

	mdadm /dev/md0 -a /dev/sda1

And very often but not always the resych hangs with
cat /proc/mdstat showing:

	md0 : active raid1 sda1[2] sdb1[1]
      	80256 blocks [2/1] [_U]
      	[>....................]  recovery =  0.0% (0/80256) finish=26.7min
speed=0K/sec


Does anybody know a solution to this problem?
Thank you very much
Alfred	


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