Citrix Xen does not have multipath service nessesary to run activated per default.
Also multipath.conf needs to be configured prior using euroNAS – if this is not set – it is possible that you will experience data loss
euroNAS uses ALUA for communication with the server – this way the server can determine which part is active one.
Before activating multipath service under Xen please ssh to the Xen Server and add following lines to the /etc/multipath.conf file
for this you can use command nano
nano /etc/multipath.conf
device {
vendor “eSSM*”
getuid_callout “/sbin/scsi_id -g -u -s /block/%n”
features “1 queue_if_no_path”
hardware_handler “1 alua”
path_grouping_policy group_by_prio
failback immediate
rr_weight uniform
rr_min_io 100
path_checker tur
no_path_retry queue
prio alua
}
If correctly set you will see following output when multipath service is enabled and you issue the command
multipath -ll
26530353739643236 dm-0 eSSM_BIO,testdisk_0
size=500G features=’3 queue_if_no_path pg_init_retries 50′ hwhandler=’1 alua’ wp=rw
|-+- policy=’round-robin 0′ prio=50 status=active
| ´- 6:0:1:0 sdc 8:32 active ready running
´-+- policy=’round-robin 0′ prio=1 status=enabled
´- 6:0:0:0 sdb 8:16 active ready running