On Tue, Jan 05, 2010 at 12:07:03PM -0800, Hunny Bunny wrote:
> Could you please clarify for me these issues
I'll try.
> First scenario:
> I'd like to create RAID5 with OCFS2 partition on my primary cluster node and
> then export this partition with MySQL data storage over NFS to other two
> cluster nodes.
> If each cluster node is running separate MySQL server, then will each MySQL
> server be able to access and use simultaneously that OCFS2 shared and
> exported over NFS data storage?
Ok, so you have three nodes. One has a single ocfs2 filesystem
exported via NFS. The other two mount that NFS filesystem but do not
mount the ocfs2 filesystem. This is a simple NFS question and the ocfs2
part doesn't matter. It is the same problem if you're using ext3 or any
other filesystem underneath NFS.
On the two remote nodes, as long as MySQL can handle the NFS
part, it will work. You'll have to check the MySQL documentation about
that. If they are accessing different database files, I'm sure it
works. If they are trying to access the same database files, you really
have to check the MySQL documentation to see if that is supported at
all, let alone over NFS. Again, the filesystem underlying the NFS
doesn't matter here.
I'm unclear as to whether the node running the ocfs2 filesystem
is also running MySQL. If the ocfs2 node is accessing the filesystem
directly at the same time other nodes are accessing it via NFS, there
may be issues with OS caching. Again, this is a concern with any
filesystem underlying NFS.
> Second scenario:
> OCFS2 partition is created on DRBD block device between primary node1 and
> secondary node2. Can I achieve the same functionality for MySQL servers as in
> the First scenario, if I export over NFS /dev/drbd0 from the primary node1 to
> other participating nodes in the cluster?
I suppose so, with the same caveats about OS caching. Do you
have no way to actually share the disk?
If you were to have node1 own the disk and nodes 2&3 run the
software (ala scenario 1), why not have node1 be a plain iSCSI server?
Then nodes 2&3 attach the device and use ocfs2 in clustered mode. This
gives you the local filesystem view and takes NFS out of the picture.
Joel
--
"You must remember this:
A kiss is just a kiss,
A sigh is just a sigh.
The fundamental rules apply
As time goes by."
Joel Becker
Principal Software Developer
Oracle
E-mail: [email protected]
Phone: (650) 506-8127
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