[DRBD-user] drbd 8 - Failure: (104) Can not open backing device.

Philipp Reisner philipp.reisner at linbit.com
Thu Jul 5 23:45:09 CEST 2007

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


On Wednesday 04 July 2007 17:58:09 Daniele Ciarelli wrote:
> Hello everybody
> I have a problem configuring DRBD, my server configuration is this:
>
> Harddisks are configured in Raid 1 mode
> Operating system: Centos5
> Kernel version: 2.6.18-8
> Drbd version: 8.0.3 (api:86/proto:86)
>
> This is my drbd.conf
>
> resource mysql {
>   protocol C;
>
>  startup { wfc-timeout 0; degr-wfc-timeout 120; }
>   disk    { on-io-error detach; }
>   net     { timeout 60; connect-int 10; ping-int 10;
>             max-buffers 2048; max-epoch-size 2048; }
>   syncer  { rate 4M; } # sync when r0 and r1 are finished syncing.
>
>   on server1 {
>     device    /dev/drbd0;
>     disk
> /dev/mapper/ddf1_4035305a8680c327202020202020202028661c7b3a354a45p8;
>     address   192.168.0.1:7789;
>     meta-disk internal;
> }
>
>   on server2 {
>     device    /dev/drbd0;
>     disk
> /dev/mapper/ddf1_4035305a8680c3272020202020202020b82fe21f3a354a45p3;
>     address   192.168.0.2:7789;
>     meta-disk internal;
> }
> }
>
> The "disk" is a partition of a hard drive that was formatted with the
> ext3 file system during the installation.
> I tried to format this partition with ext2 but didn't succeed. This
> partition is not mounted by default.
>
> The "device" is a device file.
>
> [root at server1 dev]# file /dev/drbd0
> /dev/drbd0: block special (147/0)
>
> When starting DRBD i receive the following error:
>
> [root at server1 dev]# /etc/init.d/drbd start
> Starting DRBD resources:    [ d0 Failure: (104) Can not open backing
> device.
>
> cmd /sbin/drbdsetup /dev/drbd0 disk
> /dev/mapper/ddf1_4035305a8680c327202020202020202028661c7b3a354a45p8
> /dev/mapper/ddf1_4035305a8680c327202020202020202028661c7b3a354a45p8
> internal --set-defaults --create-device --on-io-error=detach  failed!
>
> Can anyone help me with this configuration?
>

Hi,

See here:
http://lists.linbit.com/pipermail/drbd-cvs/2007-June/001571.html

There is a bug in < 8.0.5. DRBD will fail to accept device names
longer than 31 characters.

Workaround: Use shorter device names (e.g. a symlink).
Permanent solution: Available with drbd-8.0.5 (not yet released)

-phil



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