[DRBD-user] drbd -> disk /dev/???

Diego Julian Remolina diego.remolina at ibb.gatech.edu
Tue Mar 14 15:55:34 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.


Alfredo,

If you only have the / partition you cannot use drbd. Remember that 0.7.X cannot mount the drbd 
partition on both machines, so / cannot be used configured with drbd.  Maybe 0.8 will allow 
something like that, but even with 0.8 I am not totally sure that will be possible as each system 
needs to have its own /dev and /proc trees, etc.

You need to repartition your drives and set aside a partition to be exclusively used for drbd. 
Since you are going to repartition your hard drive you should also make a separate partition just 
for the metadata.  Something like

After configuring mirrors:
/dev/md0 for /boot
/dev/md1 for /
/dev/md2 for /var (A separate var is always recommended so that if var fills up your system will 
still be able to work)
/dev/md3 for /drbdmounted
/dev/md4 for metadata (Has to be 128MB big per drbd device you intend to use).

Then your fstab will include mount points for everything, except /deb/md3 and /dev/md4. You do not 
automatically mount drbd partitions from fstab, you do it with heartbeat.

You will use /dev/md3 on /etc/drbd.conf and then you will actually mount /dev/drbd0 on /drbdmounted.

Diego

Alfredo Pagano wrote:
> Hi DRBD guru, perhaps a stupid question, but I hope that u can help me.
> 
> This is my /etc/drbd.conf
> 
> vm:~# more /etc/drbd.conf
> resource drbd0 {
> protocol C;
> 
> startup {
> wfc-timeout 1; # 2 minutes.
> }
> 
> net {
> }
> 
> syncer {
> rate 100M;
> }
> 
> on HOST_2 {
> device /dev/drbd0;
> disk /dev/???;
> address 192.168.1.200:7788;
> meta-disk internal;
> }
> 
> on HOST_2 {
> device /dev/drbd0;
> disk /dev/???;
> address 192.168.1.100:7788;
> meta-disk internal;
> }
> }
> 
> 
> The problem is that on my 2 machine I have a RAID 1 with :
> 
> ~# df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/md0              111G   12G   94G  11% /
> tmpfs                1014M     0 1014M   0% /dev/shm
> 
> so, I don't know what I must put as "disk" ; if I set /dev/md0
> ~# /etc/init.d/drbd start
> Starting DRBD resources:    [ d0 Lower device (/dev/md0) is already mounted
> cmd /sbin/drbdsetup /dev/drbd0 disk /dev/md0 internal -1  failed!
> 
> if I create a new device with
> mknod -m 777 /dev/prova b 147 0
> 
> and set /dev/prova like disk in /etc/drbd.conf I receive
> 
> :~# /etc/init.d/drbd start
> Starting DRBD resources:    [ d0 Can not open lower device '/dev/prova': 
> Read-only file system
> 
> cmd /sbin/drbdsetup /dev/drbd0 disk /dev/prova internal -1  failed!
> 
> Any suggest, comment, (flout) ?
> 
> Thanks in advance and best regards.
> 
> Alfredo
> 
> 
> _______________________________________________
> drbd-user mailing list
> drbd-user at lists.linbit.com
> http://lists.linbit.com/mailman/listinfo/drbd-user




More information about the drbd-user mailing list