[DRBD-user] mkfs on a drbd partition hangs in drbd_al_begin_io

Lars Ellenberg lars.ellenberg at linbit.com
Thu May 3 14:09:32 CEST 2007

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Thu, May 03, 2007 at 01:23:19PM +0200, Håkan Engblom wrote:
> Hi,
> Some background: drbd-version is 0.7.22, running on a Montavista Linux 
> dirstribution  2.6.10_mvl4
> I've seen that sometimes when doing mkfs on a drbd-partition, the system 
> seem to hang in a drbd-function in kernel-space.
> The problem has been reported once before to this mailing-list, in February 
> 2006, a thread called "mkfs hangs with lastest drbd branch build and FC4 
> kernel" (I thin it is the same problem) and it has also been observed by 
> others (seen when searching for "drbd_al_begin_io hangs" in google)
> However I've not seen any soultion to the problem.
> So far what I've been able to establish that the process seem to hang in 
> the dbrd-function mentioned above, and I also know that it hangs 640 bytes 
> into the function. When looking at the source code of this function, my 
> guess is that it hangs on "spin_lock_irq(&mdev->al_lock);".
> Is this a known problem and does anyone know of a soultion ?

hanging in "spin_lock_irq" translates to a hard lockup of the machine.
so, this is most likely not the correct guess.

what exactly are the symptoms of that "hang"?
do the numbers in /proc/drbd move, still?

can you reproduce this with some different kernel,
preferably plain kernel.org?

does it hang only when "Connected" or also when "StandAlone"?

does running "while true; do sync; usleep 1; done" help?
  when run on the Primary?

is this on a software raid?
does it help doing this without software raid?

: Lars Ellenberg                            Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
: Vivenotgasse 48, A-1120 Vienna/Europe    http://www.linbit.com :
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