For example, the output displayed by this command might look something like this:
Node No. Avail Free Waits
0 50000 50000 na
1 50000 50000 na
■
Avail: Number of locks available.
■
Free: Number of locks in use.
■
Waits: Number of transactions that have waited for a lock.“na” (not applicable) if all locks
are available.
To change the number of locks, use the following command:
hadbm set NumberOfLocks
The hadbm restarts all the nodes, one by one, for the change to take eect. For more
information on using this command, see
“Conguring HADB” in Sun GlassFish Enterprise
Server 2.1 High Availability Administration Guide
.
Timeouts
This section describes some of the timeout values that aect performance.
JDBC connection pool timeouts
These values govern how much time the server waits for a connection from the pool before it
times out. In most cases, the default values work well. For detailed tuning information, see
“Tuning JDBC Connection Pools” on page 77.
Load Balancer timeouts
Some values that may aect performance are:
■
response-timeout-in-seconds -The time for which the load balancer plug-in will wait for a
response before it declares an instance dead and fails over to the next instance in the cluster.
Make this value large enough to accommodate the maximum latency for a request from the
server instance under the worst (high load) conditions.
■
health checker: interval-in-seconds - Determines how frequently the load balancer pings the
instance to see if it is healthy. Default value is 30 seconds. If the
response-timeout-in-seconds is optimally tuned, and the server doesn’t have too much
trac, then the default value works well.
■
health checker: timeout-in-seconds - How long the load balancer waits after “pinging” an
instance. The default value is 100 seconds.
The combination of the health checker’s interval-in-seconds and timeout-in-seconds values
determine how much additional trac goes from the load balancer plug-in to the server
instances.
TuningHADB
Chapter6 • TuningforHigh-Availability 115
