FAQs// Fibre Channel Cluster

How to configure Citrix Xen for euroNAS SAN Cluster

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