Hi Fernando / Christian,
Many thanks for getting back to me.
Slow writes are acceptable; most of our VM's are small web servers with
low traffic. My aim is to have a fully self-contained two server KVM
cluster with live migration, no external storage and the ability to
reboot either node with zero VM downtime. We seem to be "almost there",
bar a hiccup when the self-heal is in progress and some minor grumbles
from sanlock (which might be fixed by the new sanlock in RHEL 6.3)
Incidentally, the logs shows a "diff" self heal on a node reboot:
[2012-07-09 16:04:06.743512] I
[afr-self-heal-algorithm.c:122:sh_loop_driver_done]
0-gluster-rep-replicate-0: diff self-heal on /box1-clone2.img:
completed. (16 blocks of 16974 were different (0.09%))
So, does this log show "Granular locking" occurring, or does it just
happen transparently when a file exceeds a certain size?
many thanks
Jake
On 07/09/2012 04:01 PM, Fernando Frediani (Qube) wrote:
Jake,
I haven’t had a chanced to test with my KVM cluster yet but it should be
a default things from 3.3.
Just be in mind that running Virtual Machines is NOT a supported things
for Redhat Storage server according to Redhat Sales people. They said
towards the end of the year. As you might have observed performance
specially for write isn’t any near fantastic.
Fernando
*From:*[email protected]
[mailto:[email protected]] *On Behalf Of *Christian Wittwer
*Sent:* 09 July 2012 15:51
*To:* Jake Grimmett
*Cc:* [email protected]
*Subject:* Re: [Gluster-users] "Granular locking" - does this need to be
enabled in 3.3.0 ?
Hi Jake
I can confirm exact the same behaviour with gluster 3.3.0 on Ubuntu
12.04. During the self-heal process the VM gets 100% I/O wait and is locked.
After the self-heal the root filesystem was read-only which forced me to
do a reboot and fsck.
Cheers,
Christian
2012/7/9 Jake Grimmett <[email protected]
<mailto:[email protected]>>
Dear All,
I have a pair of Scientific Linux 6.2 servers, acting as KVM
virtualisation hosts for ~30 VM's. The VM images are stored in a
replicated gluster volume shared between the two servers. Live migration
works fine, and the sanlock prevents me from (stupidly) starting the
same VM on both machines. Each server has 10GB ethernet and a 10 disk
RAID5 array.
If I migrate all the VM's to server #1 and shutdown server #2, all works
perfectly with no interruption. When I restart server #2, the VM's
freeze while the self-heal process is running - and this healing can
take a long time.
I'm not sure if "Granular Locking" is on. It's listed as a "technology
preview" in the Redhat Storage server 2 notes - do I need to do anything
to enable it?
i.e. set "cluster.data-self-heal-algorithm" to diff ?
or edit "cluster.self-heal-window-size" ?
any tips from other people doing similar much appreciated!
Many thanks,
Jake
jog <---at---> mrc-lmb.cam.ac.uk <http://mrc-lmb.cam.ac.uk>
_______________________________________________
Gluster-users mailing list
[email protected] <mailto:[email protected]>
http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
--
Dr Jake Grimmett
Head Of Scientific Computing
MRC Laboratory of Molecular Biology
Hills Road, Cambridge, CB2 0QH, UK.
Phone 01223 402219
Mobile 0776 9886539
_______________________________________________
Gluster-users mailing list
[email protected]
http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
