[DRBD-user] Kernel Oops on peer when [removing LVM snapshot] receiving DISCARD/TRIM command

Lars Ellenberg lars.ellenberg at linbit.com
Thu Jun 25 23:47:49 CEST 2015

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


On Tue, Jun 23, 2015 at 01:15:39PM +0100, Paul Gideon Dann wrote:
> OK, I think I finally discovered the root trigger for this. The problem
> seems to be the TRIM that is sent down through DRBD by lvremove. When
> removing the LV, lvremove issues a TRIM on the underlying storage, which in
> this case is DRBD. DRBD (which supports TRIM) sends the command over the
> wire, and this apparently triggers some bug at the other end.
> (Incidentally, the local disk is SSD; the bug has triggered both with SSD
> and rotational remote disks.)
> 
> The workaround is to set "issue_discards = 0" in /etc/lvm/lvm.conf. After
> initial testing, it seems to have fixed the issue completely, and I'm not
> fussed about the loss of automatic TRIMs.
> 
> Hope this helps someone else in the same situation!
> 
> Is there a process for bug reporting?

You are using some ubuntu 3.16.whatever kernel.
That should be roughly equivalent to "drbd 8.4.4".

That bug (secondary bombs out when receiving TRIM) is most likely
already fixed, we would receive a flood of complaints otherwise.

*IF* you can still reproduce with more recent DRBD,
this list is just fine for reporting it.

	Lars Ellenberg




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