[DRBD-user] DRBD over an existing filesystem

[En Chiang Lee]

Hi,

I was trying to mirror an existing ext3 filesystem using drbd to another
node in an OpenSSI cluster, so I associated /dev/nbd/0 with /dev/hde2.

  on dlssi3 {
    device=/dev/nbd/0
    disk=/dev/hde2
    address=15.70.191.200
    port=7788
    meta-disk=internal
    meta-index=-1
  }

With this, I am able to mount the filesystem. However, when I try fsck
on /dev/nbd/0, I get the following error:

[root at dlssi3 root]# fsck /dev/nbd/0
fsck 1.32 (09-Nov-2002)
e2fsck 1.32 (09-Nov-2002)
/: recovering journal
The filesystem size (according to the superblock) is 2560351 blocks
The physical size of the device is 2527583 blocks
Either the superblock or the partition table is likely to be corrupt!
Abort<y>? yes

In the archives, there is mention of using "size=<somesize>", but that
is deprecated according the the sample drbd.conf. (If I was to use size=
how would the value be specified? fs blocks? GB?)

I'm trying this with drbd-0.7_pre5.

How would I go about using drbd on an existing file system? I was hoping
to do this so that I could take an existing root partition and have it
mirrored across to another node in the cluster, and so have CFS/DRBD
failover the root filesystem.

Thanks,
En Chiang