Mailing List Archive

Questions about Pacemaker, corosyns DRBD and MySQL
Hi guys,

I've got a running HA Cluster with shared storage on RHEL 5 on s390x. It
works fine but I've had to do some VM modifications underneath the
covers to adequately implement a safe STONITH package due to RACF
policies and so on.

I'm starting to experiment with RHEL 6 and I think a great solution for
me would be to implement DRBD with Pacemaker and Corosync since I
believe it would release me from the VM modifications that I'd really
like to avoid. I'm having a bit of a difficult time understanding how
DRBD works to be honest. All of the examples show how to set up the
cluster and then create a partition on both nodes for DRBD but I'm
really lacking a deep understanding on how this works and so I'm a bit
confused.

I currently have the cluster built and mysql resource enabled and
working. Regarding the DRBD partition that I create on each node - will
this partition hold a database? For instance, I have 3 databases created
- > wiki, drupal and testDB. Should I create a separate partition on
each node for each one of these databases and insert them into DRBD
config? So in effect I would have 3 separate filesystems /var/lib/wiki,
/var/lib/drupal and /var/lib/testDB ? Or is this DRBD partition a sort
of messaging partition that sits outside the database directories
themselves and handles the transaction messaging to the actual database?

Know what I mean?

-tks
Mike


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Re: Questions about Pacemaker, corosyns DRBD and MySQL [ In reply to ]
Sorry, i can't speak to RH since we run SLES. There have been some very recent fixes for it on s390x.
I can't remember which component had the issues - i think pacemaker, not corosync - but basically it couldn't shutdown the domain controller without the cluster getting totally confused. It was using little endian in places where it needed to be big! SUSE put out those fixes on Dec 27.
You should check that you don't have a problem shutting down the DC node and contact RH if you do.

Hope to save you the same fun :)


Marcy


-----Original Message-----
From: linux-ha-bounces@lists.linux-ha.org [mailto:linux-ha-bounces@lists.linux-ha.org] On Behalf Of mike
Sent: Friday, January 17, 2014 1:58 PM
To: linux-ha@lists.linux-ha.org
Subject: [Linux-HA] Questions about Pacemaker, corosyns DRBD and MySQL

Hi guys,

I've got a running HA Cluster with shared storage on RHEL 5 on s390x. It works fine but I've had to do some VM modifications underneath the covers to adequately implement a safe STONITH package due to RACF policies and so on.

I'm starting to experiment with RHEL 6 and I think a great solution for me would be to implement DRBD with Pacemaker and Corosync since I believe it would release me from the VM modifications that I'd really like to avoid. I'm having a bit of a difficult time understanding how DRBD works to be honest. All of the examples show how to set up the cluster and then create a partition on both nodes for DRBD but I'm really lacking a deep understanding on how this works and so I'm a bit confused.

I currently have the cluster built and mysql resource enabled and working. Regarding the DRBD partition that I create on each node - will this partition hold a database? For instance, I have 3 databases created
- > wiki, drupal and testDB. Should I create a separate partition on each node for each one of these databases and insert them into DRBD config? So in effect I would have 3 separate filesystems /var/lib/wiki, /var/lib/drupal and /var/lib/testDB ? Or is this DRBD partition a sort of messaging partition that sits outside the database directories themselves and handles the transaction messaging to the actual database?

Know what I mean?

-tks
Mike


_______________________________________________
Linux-HA mailing list
Linux-HA@lists.linux-ha.org
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems
_______________________________________________
Linux-HA mailing list
Linux-HA@lists.linux-ha.org
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems