Tuning LogBufferSize

Begin with the default value. Look for HIGH LOAD informational messages in the history files. All the relevant messages will contain tuple log or simply log, and a description of the internal resource contention that occurred.

Under normal operation the log is reported as 70 to 80% full. This is because space reclamation is said to be “lazy.” HADB requires as much data in the log as possible, to recover from a possible node crash.

Use the following command to display information on log buffer size and use:

hadbm resourceinfo --logbuf

For example, output might look like this:

Node No.     Avail         Free Size
0            44            42
1            44            42

The columns in the output are:

• Node No.:The node number.

• Avail: Size of buffer, in megabytes.

• Free Size: Free size, in MB, when the data volume is larger than the buffer. The entire buffer is used at all times.

  Change the size of the log buffer with the following command:

  hadbm set LogbufferSize

  This command restarts all the nodes, one by one, for the change to take effect. For more information on using this command, see Configuring HADB in Sun GlassFish Enterprise Server 2.1 High Availability Administration Guide.