[Linux-cluster] High availability xen cluster

[Maciej Bogucki]

> There are three disks in each data centre. Currently I only use the disks
> in rza.
> 
> At the moment I'm testing with a two node cluster. The virtual machines are
> on SAN disks and I can live migrate from one node to the other one. But
> what I have to cover is the disaster. What happens when the fabric in rza
> crashes? My virtual maschines are unavailable. What I'm thinking about is a
> hardware based
> mirroring between the both fabrics and break up the mirror when the
> disaster happens or we need to power off the storage for maintenance. But
> my problem is that I see duplicate pv id's in this situation. I cannot
> mirror based on lvm because it is too slow.

Do You want do implement automatic failover or manual?
You need hardware based mirroring - I'm sure that Hitachi support it(but
it cost come $ for license). The second choice is DRBD[1] with fe. iSCSI
or GNBD, but You have SAN which is better.
If You need automatic failover, You have to set device-mapper-multipath
with Active/Standby configuration where Active is Your rza and Standby
Your secondary rzb[2]. In this case You have to set also synchronous
replication both side.


[1] - http://www.drbd.org/
[2] -
http://storagefoo.blogspot.com/2006/08/linux-native-multipathing-device.html

Best Regards
Maciej Bogucki