[DRBD-user] Understanding degr-wfc-timeout

Andrew Gideon ag928272 at gideon.org
Mon Dec 6 17:26:22 CET 2010


On Mon, 06 Dec 2010 12:48:50 +0100, Lars Ellenberg wrote:

>> Starting drbd:  Starting DRBD resources: [ drbd1 Found valid meta data
>> in the expected location, 16105058304 bytes into / dev/xvdb1.
>> d(drbd1) drbd: bd_claim(cfe1ad00,cc00c800); failed
>> [d108e4d0;c0478e79;1] 1: Failure: (114) Lower device is already
>> claimed. This usually means it is mounted.
> 
> There.  It cannot even attach.
> Because it cannot attach, it cannot read it's meta data. Thus it does
> not know anything about itself.

Ah!  I noticed that, but it didn't click to me that this would be 
related, so I just put that issue off.

>> [drbd1] cmd /sbin/drbdsetup 1 disk /dev/xvdb1 /dev/xvdb1 internal
>> --set- defaults --create-device  failed - continuing!
> 
> You better make sure xvdb1 is not used by someone else at the time your
> drbd tries to attach it.
> 
> You may need to fix your fstab, or your lvm.conf, or your initrd, or
> whatever other "magic" is going on there.

LVM; the underlying device is being activated by LVM so I need to block 
that.  I'll make the change and try again.

[...]

>> FWIW, I've also posted in the thread "RedHat Clustering Services does
>> not fence when DRBD breaks" trying to understand the fencing process. 
>> I think I managed to suspend all I/O in the case of a fence failure
>> (the handler returning a value of 6), but I'm not sure.  Does:
>> 
>>  1: cs:WFConnection ro:Primary/Unknown ds:UpToDate/DUnknown C s----
>>     ns:0 nr:0 dw:4096 dr:28 al:1 bm:3 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b
>>     oos:0
>> 
>> indicate suspension?  Is that what "s----" means?
> 
> at that position, yes, that means application io is s: suspended, or r:
> running/resumed.
> you can manually resume with "drbdadm resume-io"

Perfect.  Thanks.

> 
>> I've failed to find documentation for that bit of string in /proc/drbd.
> 
> Is that so.

Yes.  I would have thought it to be in

http://www.drbd.org/users-guide/ch-admin.html#s-proc-drbd

but if so then I'm missing it.  Or is it elsewhere?

Thanks again...

	Andrew



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