If you use network file system version 3 (NFSv3) for storing transaction recovery logs, and you want to use automated peer recovery, you must first disable file locking.
Before you begin
Why and when to perform this task
WebSphere Application Server obtains an exclusive lock on the physical recovery log files whenever it is instructed to perform recovery processing, and releases this lock when it is instructed to pass ownership of the logs to another server. Access to a recovery log is only performed when the exclusive lock is held.
NFSv3 supports exclusive file locks, but holds them on behalf of a failed host until that host can restart. In this context, the host is the physical machine running the application server that requested the lock and it is the restart of the host, not the application server, that eventually triggers the locks to release. See How to choose between automated and manual transaction peer recovery for more information.
To provide a more appropriate failover behavior, you can either use manual failover and configure the system as described in Configuring manual peer recovery for the transaction service, or you can disable the use of exclusive file locking.
Steps for this task
What to do next
Having taken steps to mitigate the risk to recovery log integrity when locking is disabled, you can tune the heartbeating parameters of the WebSphere Application Server HA framework to change the conditions under which a server is considered failed. By considering the characteristics of applications, network, and peak workloads, determine an acceptable period of time after which the likelihood of an incorrectly diagnosed server failure is acceptably small.
There is a trade-off between reducing the risk of an incorrect diagnosis of server failure and increasing the time it takes for automated failover and peer recovery to occur. By default, a server is considered to have failed after 20 heartbeats, with a 10-second frequency, are missed. These defaults are custom properties of the core group that can be modified.
Related concepts
Transactional high availability
High availability manager
Related tasks
Configuring manual peer recovery for the transaction service
Configuring automated peer recovery for the transaction service
Related information
How to choose between automated and manual transaction peer recovery