[DRBD-user] drbd - configuring without secondary in place

Noah Dain noahdain at gmail.com
Thu Sep 13 17:39:32 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 9/13/07, Stefan Lesicnik <stefan at lsd.co.za> wrote:
> Hi,
> I've searched for quite a while and havent been able to find any
> solution to a current problem we have.
> I am setting up a HA server and want to use drbd. I have tested drbd and
>  it seems to work well.
> The problem comes in that I need to configure our new server with drbd
> and have it become the primary, but the secondary wont be available
> until i reinstall it, install drbd and copy the drbd.conf file in.

I'm doing something similar here.  One machine is up (fresh install),
but I'm waiting on another machine to become available before I can
make it the secondary.

I'm running debian etch (4.0).

> I didnt want to do that step all on one day, i had it planned like this
> Install new server
> Configure drbd (point to a dummy secondary server?)
> Make drbd the primary
> Configure new server
> Shut down old server
> Promote new server to our main server
> Configure old server with drbd as failover for new server
> >From what i've seen, i cant seem to promote drbd to primary if it cant
> see the secondary. Is this correct?  Any way around this?  Also, it
> seems you cant mount /dev/drbd0 if it is not consistant and a drbd primary.

you can force it to be the primary with drbdadm.  heartbeat can also
be set up to do this.  Although in my situation, I've never had a drbd
device show as inconsistant.

for the drbd resource(s) in question, I have these settings ( in
drbd.conf, obviously ):
startup {
        wfc-timeout 10;     ## how long to wait before going ahead
without other cluster node
        degr-wfc-timeout 20;    ## degraded-cluster at boot timeout

Then I had to change the heartbeat script that handles drbd (
/etc/ha.d/resource.d/drbddisk ), as it wasn't mounting the drbd
device. I changed "sleep 1" to "sleep 5" (it's the only 'sleep'
command used in that script).

so now on a system startup the drbd init script runs and the drbd
device comes up as secondary.  heartbeat then starts and about a
minute later it promotes the drbd device(s) to primary and mounts the

my /etc/ha.d/haresources line looks like this:
myserver drbddisk::drbdres0 Filesystem::/dev/drbd0::/drbd/res0::ext3

once i get the failover machine online, I may need to tweak the
timeout settings and what not.  Afraid I can't be of much more help on
that just yet.  I still need to learn the finer points of drbd and

> I would be really grateful for some advice around this.
> thanks in advance!
> Stefan
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Noah Dain
"The beatings will continue, until morale improves" - the Management

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