Re: [ClusterLabs] DRBD or SAN ?
Once upon a time, Ian said: > I think a big advantage compared to native replication is that DRBD offers > synchronous replication at the block level as opposed to the transaction > level. However, just like RAID is not a replacement for backups, DRBD is IMHO not a replacement for database replication. DRBD would just replicate database files, so if for example file corruption would be copied from host to host. When something provides a native replication system, it is probably better to use that (or at least use it at one level). -- Chris Adams ___ Users mailing list: Users@clusterlabs.org http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
Re: [ClusterLabs] Question about fence_mpath
Once upon a time, Ken Gaillot said: > You only want pcmk_host_check=none if the fence device can fence either > node. If the device can only fence one node, you want > pcmk_host_list= Hmm, I guess I still don't understand how to use fence_mpath to handle fencing. Do I set up a separate STONITH device for each node, with that node's key (same as in /etc/multipath.conf)? -- Chris Adams ___ Users mailing list: Users@clusterlabs.org http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
Re: [ClusterLabs] Question about fence_mpath
Once upon a time, Seth Reid said: > This confused me too when I set up my cluster. I found that everything > worked better if I didn't specify a device path. I think there was > documentation on Redhat that led me to try removing the "device" options. fence_mpath won't work without device(s). However, I figured out my problem: I needed to set pmck_host_check=none (both nodes in my cluster can handle fencing). Then everything seems to work. -- Chris Adams ___ Users mailing list: Users@clusterlabs.org http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
Re: [ClusterLabs] Question about fence_mpath
Once upon a time, Seth Reid said: > I've had a similar problem. Make sure that the /dev/mapper object above > isn't a symlink. In my multiparth.conf, I had added an alias to a device > name, like that, to make it easier, but if I pointed my fencing at that, it > didn't work. However, I could point directly to the object that the symlink > pointed to, and it work. I actually had better luck not even specifying a > device at all. It found the right one. But the multipath devices are always symlinks - how do you access it? The only "real" devices are /dev/dm-, but those names are not stable, so you can't use those for anything. -- Chris Adams ___ Users mailing list: Users@clusterlabs.org http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
Re: [ClusterLabs] Question about fence_mpath
So, I'm still not getting fence_mpath working. This is all on CentOS 7.
Here's what I did:
- on each node, put a unique "reservation_key" in /etc/multipath.conf
defaults{} section (node1=20170001 and node2=20170002)
- created the STONITH device on node1 with:
pcs stonith create multipath fence_mpath
devices=/dev/mapper/36000d31001309643 key=20170001 meta
provides=unfencing
It creates, but any time anything tries to fence (manually or by
rebooting a node), I get errors in /var/log/messages. Trying to
manually fence a node gets:
# pcs stonith fence node2 --off
Error: unable to fence 'node2'
Command failed: No such device
Another issue I run into is that fence_mpath tries to access/write to
/var/run/cluster/mpath.devices, but nothing else creates that directory
(and it seems that fence_mpath tries to read from it before writing it
out).
Anybody using fence_mpath as a STONITH device with pacemaker/corosync on
CentOS 7?
--
Chris Adams
___
Users mailing list: Users@clusterlabs.org
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Re: [ClusterLabs] Question about fence_mpath
Once upon a time, Seth Reid said:
> This is part of my multipath.conf that shows the key.
> $ cat /etc/multipath.conf
> defaults {
> user_friendly_names yes
> find_multipaths yes
> reservation_key 33c5
> }
Ah, I should have checked the multipath.conf man page (was just looking
at the fence_mpath page). Thanks!
--
Chris Adams
___
Users mailing list: Users@clusterlabs.org
http://lists.clusterlabs.org/mailman/listinfo/users
Project Home: http://www.clusterlabs.org
Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
Bugs: http://bugs.clusterlabs.org
[ClusterLabs] Question about fence_mpath
I am trying to set up a new cluster using fence_mpath. I'm not sure what to use for the "key" value though. The man page talks about it unique to each node (but you only create the STONITH object from one node, right?). It also says it has to be set in /etc/multipath.conf but then doesn't say how/where. -- Chris Adams ___ Users mailing list: Users@clusterlabs.org http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
