[DRBD-user] DRBD Initial Sync error receiving RSDataRequest, l: 24!

Ian MacDonald ian+drbd at dotto-one.com
Wed Jul 16 19:02:11 CEST 2014

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


Lars,

thankyou for the useful insight,  I made some other observations and have a
few questions below.

cheers,
Ian

On my list of test scenarios is to test with some newer Debian
8/testing/Jessie packages (8.4.4-1).

But I really need to stick with Debian Stable in production, so even if
this resolves the problem, I would like to have the 8.3.13 stack working on
multiple Debian Stable servers.

Before I go testing other scenarios that I can't maintain in production,
I'd like to try and get the 8.3 stack working.

Your second point on the max BIO size is interesting.  I didn't notice,
likely because I did not understand what it means. It led me to find
http://lists.linbit.com/pipermail/drbd-user/2011-August/016659.html

suggesting again, some of these VPS hosts confuse the DRBD calculation for
max BIO size. I saw the same Error using LVM on backup, so I might assume
this BIO size stays the same even switching to LVM.

Question 1: Is there any known way to workaround the max BIO size issue on
the 8.3.X stack?

>From what I have quickly learned, it has something to do with maximum
discards, and is a metadata attribute.

In the 8.4 documentation (http://www.drbd.org/users-guide/re-drbdmeta.html)
I see this parameter during mdcreate

--peer-max-bio-size=val (metadata versions v06, v07, and v08)

This feature is not appearing in 8.3.

So, I am going to try and use 8.4 userland tools (which I can pull down
from the Debian 8 repository on my Debian 7 box easily) and re-create my
metadata on host backup with a --peer-max-bio=4096 and resolve this issue,
and then switch back to 8.3 userland to interpret my resource configuration
and interop with my kernels 8.3 modules (assuming mixing kernel module and
userland 8.3/8.4 is not a good idea).

Question 2: Do you think this metadata fix is the right direction?

Question 3:Is this  'I'm sure it has been fixed since' you are referring
to?  If not, is there a patch or such that I might easily be able to submit
to Debian package maintainers upstream.

cheers,
Ian


On Wed, Jul 16, 2014 at 12:00 PM, Lars Ellenberg <lars.ellenberg at linbit.com>
wrote:

> On Mon, Jul 14, 2014 at 02:46:01PM -0400, Ian MacDonald wrote:
> > I have two hosts configured as Primary-Secondary on Debian 7 (current
> > stable) and DRBD (debian packaged 8.3.13-2)
>
> How about you upgrade your drbd module and userland.
>
> > Jul 14 12:06:05 backup kernel: [22632331.366571] block drbd0: max BIO
> size
> > = 4294966784
>
> That looks broken.
> I'm sure it has been fixed since.
>
>         Lars
>
> --
> : 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.
> __
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