5.5 HP StorageWorks X9300 Network Storage Gateway Administrator Guide (AW539-96007, March 2011)

After failing back the node, determine whether the failback completed fully. If the failback is not
complete, contact HP Support for assistance.
NOTE:
A failback might not succeed if the time period between the failover and the failback is too short, and
the primary server has not fully recovered. HP recommends ensuring that both servers are up and
running and then waiting 60 seconds before starting the failback. Use the ibrix_server -l
command to verify that the primary server is up and running. The status should be Up-FailedOver
before performing the failback.
Using network interface monitoring
With network interface monitoring, one file serving node monitors another file serving node over a
designated network interface. If the monitoring server loses contact with its destination server over
the interface, it notifies the management console. If the management console also cannot contact the
destination server over that interface, it fails over both the destination server and the network interface
to their standbys. Clients that were mounted on the failed-over server do not experience any service
interruption and are unaware that they are now mounting the file system on a different server.
Unlike X9000 clients, NFS and CIFS clients cannot reroute file requests to a standby if the file serving
node where they are mounted should fail. To ensure continuous client access to files, HP recommends
that you put NFS/CIFS traffic on a user network interface (see “Preferring network
interfaces” on page 65), and then implement network interface monitoring for it.
Comprehensive protection of NFS/CIFS traffic also involves setting up network interface monitoring
for the cluster interface. Although the management console will eventually detect interruption of a file
serving node’s connection to the cluster interface and initiate segment failover if automated failover
is turned on, failover will occur much faster if the interruption is detected via network interface
monitoring. (If automated failover is not turned on, you will begin to see file access problems if the
cluster interface fails.) There is no difference in the way that monitoring is set up for the cluster interface
and a user network interface. In both cases, you set up file serving nodes to monitor each other over
the interface.
Sample scenario
The following diagram illustrates a monitoring and failover scenario in which a 1:1 standby relationship
is configured. Each standby pair is also a network interface monitoring pair. When SS1 loses its
connection to the user network interface (eth1), as shown by the red X, SS2 can no longer contact
SS1 (A). SS2 notifies the management console, which then tests its own connection with SS1 over
eth1 (B). The management console cannot contact SS1 on eth1, and initiates failover of SS1’s
segments (C) and user network interface (D).
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