[DRBD-user] DRBD

Diego Julian Remolina diego.remolina at ibb.gatech.edu
Mon Feb 13 15:10:45 CET 2006

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


DRBD 0.7.X cannot be used on an active/active configuration.  This means that if Node1 is drbd 
primary, you cannot mount the drbd partition on Node2. You seem to be trying to mount the physical 
device /dev/sda2 on Node2, which will allow you to see the contents that have been replicated 
through drbd.  However, drbd was not designed to do that.  That may be why after writing data on 
Node1, you still need to umount and mount /dev/sda2 on the slave to see changes. Remember, it was 
not meant to be used like that.

What you should do is create a folder on while drbd is primary on Node1, then go to Node2 and make 
it primary with the command:

drbdadm primary "Your-Resource-Name-Here"

cat /proc/drbd on Node1 and make sure it is now primary.

Now you can mount /opt on the secondary with
mount /dev/drbd0 /opt

Now your secondary node is master and you should see the folder you created on Node1 in /opt.

DRBD 0.8 which is currently under development will support active/active configurations.  You will 
also need an appropriate file system that can support multiple hosts writting simultaneously to it 
like GFS to get active/active.

Diego

> after i mount on master /dev/drdb0 /opt, and is ok
> 
> i do the modifications in /opt directory on master, example i made a
> directory (mkdir directorytest)
> 
> I don't understand why the new directory on master not replicate on
> slave when partition is mount (/dev/sda2 /opt)
> 
> On slave, I don't understand, when i umount and remount partition the
> replication is ok.
> 
> I must do umount and remount everytimes ?
> 
> Can you help me ?
> 
> Best regards
> 




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