[DRBD-user] recovery from "page allocation failure"

Lars Ellenberg lars.ellenberg at linbit.com
Wed Jul 17 11:27:23 CEST 2013

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

On Wed, Jul 17, 2013 at 05:25:13PM +0900, Christian Balzer wrote:
> Hello,
> On Mon, 3 Jun 2013 21:55:01 +0900 Junko IKEDA wrote:
> Better late than never...
> > Hi,
> > 
> > I got the following error while running drbd-8.3.15,
> > kernel: drbd1_receiver: page allocation failure. order:4, mode:0x20
> > 
> > and I also found some kernel tuning tips in this list.
> > http://lists.linbit.com/pipermail/drbd-user/2012-March/018036.html
> > 

Oh, I think I anwered this?
But maybe that was via our support channel...

> In the replies to this thread and the one before it was suggested that
> these events are "harmless".
> BTW, you're not mentioning what transport you're using, but I only ever
> saw these problems with IPoIB, so is that what you're using?
> On a very busy cluster with kernel 3.4.48 and DRBD 8.4.3 I was able to
> reduce these kernel messages from dozens a day to nearly none by setting
> vm/min_free_kbytes = 524288

Yes, that's a setting that should typically help.

> Lars, as this keeps popping up and always suggests DRBD to be guilty party
> even if it's not, I wonder if you guys should have some back channel talk
> with the relevant people on the kernel ML...

I don't think that would lead anywhere,
upstream kernel has the "memory compaction" meanwhile,
so it should have become much less likely to hit this situation.

Part of the issue was that there is no "physically contiguous" memory
available: even though we have free memory, it is too fragmented.

The "compaction" should cause "defragmentation" during normal
allocations, making it much less likely to fail atomic allocations due
to fragmentation.

"just use a more recent kernel" should help as well, already


: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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