Mount NFS share as hard in XenServer 6.2

By default XenServer mounts NFS SR with soft option.
That can cause the VM running on NFS to output an IO error and remount its disk as read-only.
The solution is to hard mount the NFS share. This will leave the VM to hang and wait for the share to come back online.

Edit file /opt/xensource/sm/ and uncommment existing options line under the soft_mount function and add new options line:

#options = "soft,timeo=%d,retrans=%d,%s" % (SOFTMOUNT_TIMEOUT,
# transport)
#options += ',actimeo=0'
options = "rw,tcp,bg,hard,intr,sync,noac,rsize=262144,wsize=262144,timeo=600,retrans=2,_netdev"

More info on this issue: