[Gluster-users] Brick is not connected (and other funny things)

[Marco Marino]

Hi,
I'm trying to use glusterfs with my openstack private cloud for storing
ephemeral disks. In this way, each compute node mount glusterfs in /nova
and save instances on a remote glusterfs (shared between the compute nodes,
so live migration is very fast).
I have 2 storage node (storage1 and storage2) with replica 2.
In a first configuration i've used nfs on the clients. In /etc/fstab of the
compute nodes i have:
storage1:/cloud_rootdisk /nova nfs mountproto=tcp,vers=3 0 0

This creates a single point of failure because if storage1 goes down, i
have to remount manually on storage2. And this causes the complete disk
corruption of all VMs that running on all the compute nodes. Really
funny...

In a second configuration, i've used the gluster native client with
"backupvolfile-server=storage2". i've made few tests, but it seems to work.
What i've tested:
on the compute node i have:
mount -t glusterfs -o
backupvolfile-server=server2,fetch-attempts=2,log-level=WARNING,log-file=/var/log/gluster.log
server1:/test-volume /gluster_mount

Then, I booted a vm and started to download a large file (1GB) from the vm
(so, i'm writing on the ephemeral disk stored via glusterfs). During this
download, i rebooted storage1 and the VM seems to be not corrupted (so, the
vm write only on storage2).
Can i have a confirmation about this? Is this the right way?

Next question:
When i rebooted storage1, it fails to start. it tells me that /dev/sdc1
(the partition that i'm using for the test) is corrupted. It could be a
normal behavior because the server goes down during a write. So, started
the storage1 in single user mode and xfs_repair /dev/sdc1. This make me
able to start storage1. (yuppy)
Glusterfs starts correctly, but now i have "brick1 is not connected", where
/export/brick1 is the brick that i'm using on storage1 for the volume used
for tests.
On storage2 all is ok, but i have a split brain condition. /export/brick1
on storage1 doesn't contain datas....
What can i have to do to restore /export/brick1 on storage1 ???


Thanks
MM
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