[DRBD-user] 'drbdadm connect' panic?

[Lars Ellenberg]

On Wed, Jul 18, 2007 at 04:19:02PM -0500, alex at crackpot.org wrote:
> My 2 drbd boxen are called 42 and 43.
> drbd version: 0.7.16 (api:77/proto:74)
> 
> * Today, 42 was primary.
> * A co-worker noticed that it was not connected to 43.  (42 =  
> 'st:Primary/Unknown ld:Consistent', 43 = 'st:Secondary/Unknown  
> ld:Consistent')
> * I saw that 43 said 'cs:WFConnection'.  Co-worker did 'drbdadm  
> connect' on 42, and it kernel paniced.

what cs: was 42 in, before the "drbdadm connect" ?
what is in the kernel logs,
what lead to them being disconnected in the first place?

what does the panic/oops look like?

did it panic in drbd or somewhere else?
was it an "intentional" panic?

> * 43 took over as primary as it should.
 (with out-of-date data)

> * When 42 was rebooted, it entered Secondary status and performed a  
> sync of data from 43.  Since the 2 boxes had been disconnected for  
> several days, the data on 43 was old, and the newer data from 42 was  
> overwritten.

yes.

> We're getting backup restores from tape.  We've added better  
> monitoring to catch when drbd disconnects in the future.
> 
> I am writing because up to this point I thought that a 'drbdadm  
> connect' was a fairly safe command to issue.  Are there circumstances  
> under which it should not be done, or which may cause a panic as we  
> saw today?

those would be bugs.
some of them might be fixed already,
you are 0.7.16, we are 0.7.24?

> Would doing 'drbdadm disconnect' before 'drbdadm connect'  
> have made a difference?

hard to say. maybe. probably not.

> If the 2 boxes disconnect in the future (for network failure or  
> whatever other reason), what is the safe way to get them talking again?



-- 
: Lars Ellenberg                            Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
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