[Linux-HA] Multi-state resource constraints

Andrew Beekhof beekhof at gmail.com
Wed Sep 26 02:40:27 MDT 2007


On 9/25/07, Joseph Lamoree <jlamoree at gmail.com> wrote:
> > i'm not very familiar with drbd, is this some sort of requirement it has?

i meant the need to have all the masters on the one machine

> This isn't really specific to DRBD. The privative resources could be
> anything. The actual function of these two resources is to provide a
> highly available NFS server. My plan is to put the NFS runtime data
> from /var/lib/nfs on a shared block device (drbd:nfsmd). The other
> shared block device contains a filesystem to be shared (drbd:ss). When
> the NFS service moves from one cluster node to the other, all the
> connection state information will be retained (in theory). I'm not an
> NFS guru, but I have done a good amount of testing in my lab. My plan
> it so have several DRBD resources containing files to be shared for a
> group of web servers.
>
> > > However, in reading through the information on multi state clone
> > > resources, I believe it may be better to assert the negative
> > > conditions.
> >
> > shouldn't be required.  where did you read that?
>
> http://www.linux-ha.org/v2/Concepts/MultiState
>
> I thought the proper way might be to express the rules as eliminating

both ways are equally valid, there is no one "proper" way

> all undesired states. The current configuration works fine when
> heartbeat is brought up on both nodes. The issues occur when one goes
> to standby; when it comes back, heartbeat tries to shuffle the
> resources around, and that seems to cause the problem with the second
> DRBD resource getting out of sync.

ok, i'll need logs for that

> > > I don't know if this is by design, but when a node comes back from
> > > standby, the other node will stop all its resources and then restart
> > > them -- even though the resources should stay in place on the node
> > > acting as master.
> >
> > what version do you have?  some older versions had trouble with this.
>
> heartbeat-2.1.2-3.el5.centos
>
> > > In this state, I thought I could use drbdadm up ss && drbdadm primary
> > > ss, then crm_resource -R, but that doesn't fix it up.
> >
> > try -C instead
>
> Using crm_resource -P actually seems to help, although it might be a
> coincidence.

in many ways they achieve the same result just by different means

> > can you attach the logs too?  i'd like to see how we got into this state.
>
> Hopefully the attached data helps.

/me doesn't see any attachments



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