[DRBD-user] iscsi + md0 = tell me why this is a bad idea

Artur (eBoundHost) artur at eboundhost.com
Wed Oct 22 01:12:47 CEST 2008

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

you said:
think about what can go wrong.
and how to recover from that.

what if ...
   one target breaks
   one link breaks
   one initiator breaks

how to
   do a failover.
   do a failback.
   determine "better" (more recent) data.
   determine resync direction.
   determine which areas of the disks to sync.
   determine data divergence.

I think in all areas drbd does better than nbd/iscsi + md raid1,
but I am happy to hear all ideas, and use them as inspiration
for future linux storage replication solutions.

Well the good thing about that is that you never have to guess what 
happened.  Since the md raid will lose one of the drives and still run 
on the other one, you never think about which one is current.  The one 
that does not have a connection is the one that needs to be resynced. 
And you don't have to resync the entire drbd0 volume, just however much 
you allocated through LVM to be exported.

Best Regards,


More information about the drbd-user mailing list