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

Felix Frank ff at mpexnet.de
Tue Feb 21 10:04:32 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?


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.


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