HP StorageWorks XP Cluster Extension Software Administrator Guide (T1656-96035, April 2010)

2. Choose the port that the pair/resync monitor will use, and then add the following line to the
services file:
clxmonitor nnnnn /tcp
where nnnnn is the port number. For example:
clxmonitor 22222/udp # CLX Pair/Resync Monitor
clxmonitor 22222/tcp # CLX Pair/Resync Monitor
Activating the pair/resync monitor
The pair/resync monitor detects and reacts to suspended XP Continuous Access Software links. To
activate the pair/resync monitor, set the ResyncMonitor object to YES. To activate automatic disk pair
resynchronization, set the ResyncMonitorAutoRecover object to YES.
When a RHCS service or SLE HA resource group is stopped, the pair/resync monitor is stopped for
the XP RAID Manager device group the service or resource group uses.
The pair/resync monitor does not allow online changes in the XP Cluster Extension resource
configuration file when the corresponding RHCS service or SLE HA resource group is online.
• If the ResyncMonitor object is changed to YES while the RHCS service or SLE HA resource group
is running, the pair/resync monitor is not started.
• If the ResyncMonitor object is changed to NO while the RHCS service or SLE HA resource group
is running, a running pair/resync monitor is not stopped.
CAUTION:
If a RHCS service or SLE HA resource group cannot be stopped gracefully, disable monitoring of the
device group for the service or resource group. To avoid data corruption, this task must be part of
the recovery procedure when XP Cluster Extension is deployed in the RHCS or SLE HA environment.
See “Stopping the pair/resync monitor” on page 115.
Ensure that the pair/resync monitor does not monitor and resynchronize the disk pair (device group)
from both disk array sites.
Timing considerations
XP Cluster Extension gives priority to XP disk array operations over cluster software operations. If XP
Cluster Extension invokes disk pair resynchronization or gathers information about the remote XP disk
array, XP Cluster Extension waits until the requested status information is reported. This ensures the
priority of data integrity over cluster software failover processes. This behavior can lead to failed
resources, as follows:
• XP Cluster Extension uses XP RAID Manager instances to communicate with the remote XP disk
array. Depending on the setting of the XP RAID Manager instance timeout parameter and the
number of remote instances, the service or resource group start operation can time out. This can
occur if the local XP RAID Manager instance cannot reach the remote XP RAID Manager instance.
In an SLE HA environment, the timeout value defined for the start operation can be adjusted to the
appropriate value to avoid this situation. In an RHCS environment, the timeout value depends on
the timeout value specified in script resource agent (/usr/share/cluster/script.sh).
• XP Cluster Extension tries to resynchronize disk pairs and waits until the XP RAID Manager device
group is in the PAIR state if the ApplicationStartup object is set to RESYNCWAIT. XP RAID Manager
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