[DRBD-user] Kernel hung on DRBD / MD RAID

Dan Barker dbarker at visioncomm.net
Tue Feb 21 15:50:48 CET 2012

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


>> On 02/21/2012 12:03 AM, Andreas Bauer wrote:
>> > So when vm-master is Primary, vm-slave is Secondary, and I 
>> > force-detach the
>> backing device on vm-master, DRBD will automatically make vm-slave the 
>> Primary and direct writes to that host?
>> 
>> no.
>> 
>> The secondary remains secondary. However, the primary cannot write to 
>> its local disk (seeing as it is detached), so writes are done *only* 
>> on the secondary (normally, any write is done on both nodes).
>> 
>> When the diskless node eventually gets access to a backing storage 
>> device again (the old disk or a new one), it resyncs with the UpToDate 
>> one and you're back to normal.
>> 
>> Of course, if you loose connectivity or the peer's disk, you're down 
>> to "no disk", and therefore out of operation.
>> 
>> HTH,
>> Felix
>
> Thanks, it does help. So a node can be Primary and inconsistent while 
> the opposite node is Secondary and UpToDate and read requests are
(necessarily) 
> satisfied over network. Didn't know that.
>
> regards,
>
> Andreas

and Writes!




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