Am 08.12.2015 um 02:59 schrieb Lindsay Mathieson:
Hi Udo, thanks for posting your volume info settings. Please note for
the following, I am not one of the devs, just a user, so unfortunately
I have no authoritative answers :(
I am running a very similar setup - Proxmox 4.0, three nodes, but
using ceph for our production storage. Am heavily testing gluster 3.7
on the side. We find the performance of ceph slow on these small
setups and management of it a PITA.
Some more questions
- how are your VM images being accessed by Proxmox? gfapi? (Proxmox
Gluster storage type) or by using the fuse mount?
Sorry, forgot to say that: I'm accessing the Gluster Storage via NFS
since (at least in version 3.4 of Proxmox) the gfapi method has some
problems with sockets.
- whats your underlying filesystem (ext4, zfs etc)
a dedicated ext4 partition
- Are you using the HA/Watchdog system in Proxmox?
I am now (watchdog HA), but Proxmox was running in non-HA mode at the
time of failure.
On 07/12/15 21:03, Udo Giacomozzi wrote:
esterday I had a strange situation where Gluster healing corrupted
*all* my VM images.
In detail:
I had about 15 VMs running (in Proxmox 4.0) totaling about 600 GB of
qcow2 images. Gluster is used as storage for those images in
replicate 3 setup (ie. 3 physical servers replicating all data).
All VMs were running on machine #1 - the two other machines (#2 and
#3) were *idle*.
Gluster was fully operating (no healing) when I rebooted machine #2.
For other reasons I had to reboot machines #2 and #3 a few times, but
since all VMs were running on machine #1 and nothing on the other
machines was accessing Gluster files, I was confident that this
wouldn't disturb Gluster.
But anyway this means that I rebootet Gluster nodes during a healing
process.
After a few minutes, Gluster files began showing corruption - up to
the point that the qcow2 files became unreadable and all VMs stopped
working.
:( sounds painful - my sympathies.
You're running 3.5.2 - thats getting rather old. I use the gluster
debian repos:
3.6.7 :
http://download.gluster.org/pub/gluster/glusterfs/3.6/LATEST/Debian/
3.7.6 :
http://download.gluster.org/pub/gluster/glusterfs/LATEST/Debian/jessie/
3.6.x is the latest stable, 3.7 is close to stable(?) 3.7 has some
nice new features such as sharding, which is very useful for VM
hosting - it enables much faster heal times.
I'm using the most current version provided by Proxmox APT sources.
Can 3.6 or even 3.7 Gluster nodes work together with 3.5 node? If not
I'm wondering how I could upgrade...
You might understand that I hesitate a bit to upgrade Gluster without
having some certainty that it won't make things even worse. I mean, this
is a production system..
Regards what happened with your VM's, I'm not sure. Having two servers
down should have disabled the entire store making it not readable or
writable.
I'm not sure if both servers were down at the same time (could be,
though). I'm just sure that I rebootet them rather quickly in sequence.
Right now my credo is "/never ever reboot/shutdown more than 1 node at a
time and most importantly, always make sure that no Gluster healing is
in progress/". For sure, I did not respect that when I crashed my storage.
I note that you are missing some settings that need to be set for VM
stores - there will be corruption problems if you live migrate without
them.
quick-read=off
read-ahead=off
io-cache=off
stat-prefetch=off
eager-lock=enable
remote-dio=enable
quorum-type=auto
server-quorum-type=server
"stat-prefetch=off" is particularly important.
Thanks. Is there a document that explains the reasoning behind this config?
Does this apply to volumes for virtual HDD images only? My "docker-repo"
is still "replicate 3" type but is used by the VMs themselves, not by
the hypervisor - I guess other settings apply there..
Thanks a lot,
Udo
_______________________________________________
Gluster-users mailing list
[email protected]
http://www.gluster.org/mailman/listinfo/gluster-users
