DRBD: possible deadlock in Ahead mode
Quoted 11 lines · On Wed, Aug 24, 2011 at 03:14:47PM +0000, [email protected]…
https://bugzilla.kernel.org/show_bug.cgi?id=41602
--- Comment #2 from Cyril B. <[email protected]> 2011-08-24 15:14:47 --- I can't rule out a misconfiguration, but I've been using DRBD since 8.0 on many servers and I've never seen such a thing happen. It's only happened very recently since I began using Linux 3.0 on a few servers, a few days ago.
Even if it's a temporary network failure that I've never had before:
- how comes even a drbdadm disconnect doesn't work (i.e. hangs), and I have to
reboot the primary server to be able to write on my filesystem again?
Arguably a design bug, the default disconnect waits for all current requests to be handled.
You can try to --force disconnect, though.
Quoted 2 lines
- isn't the Ahead mode supposed to not block IO if the buffer is full and/or
the secondary server is not accessible?
Well, yes, but it still needs to send some bytes (as oposed to the full data block) to the peer. And if sendmsg blocks/times out/makes no progress for whatever reason, we cannot do anything about that.
Signature · 5 lines
: Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.