Il 21/03/2013 18:14, Digimer ha scritto:

On 03/21/2013 01:11 PM, Maurizio Giungato wrote:

Hi guys,

my goal is to create a reliable virtualization environment using CentOS
6.4 and KVM, I've three nodes and a clustered GFS2.

The enviroment is up and working, but I'm worry for the reliability, if
I turn the network interface down on one node to simulate a crash (for
example on the node "node6.blade"):

1) GFS2 hangs (processes go in D state) until node6.blade get fenced
2) not only node6.blade get fenced, but also node5.blade!

Help me to save my last neurons!

Thanks
Maurizio

DLM, the distributed lock manager provided by the cluster, is designed to block when a known goes into an unknown state. It does not unblock until that node is confirmed to be fenced. This is by design. GFS2, rgmanager and clustered LVM all use DLM, so they will all block as well.

As for why two nodes get fenced, you will need to share more about your configuration.

My configuration is very simple I attached cluster.conf and hosts files.
This is the row I added in /etc/fstab:
/dev/mapper/KVM_IMAGES-VL_KVM_IMAGES /var/lib/libvirt/images gfs2 defaults,noatime,nodiratime 0 0

I set also fallback_to_local_locking = 0 in lvm.conf (but nothing change)

PS: I had two virtualization enviroments working like a charm on OCFS2, but since Centos 6.x I'm not able to install it, there is same way to achieve the same results with GFS2 (with GFS2 sometime I've a crash after only a "service network restart" [I've many interfaces then this operation takes more than 10 seconds], with OCFS2 I've never had this problem.

Thanks

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