The PHYSBUFF parameter in the Informix ONCONFIG file specifies the size of the physical log buffers in KB. These buffers are used to temporarily store the physical logs. The size of a buffer determines how often it fills and, therefore, how often it must be flushed to the physical log on disk.

The default value of PHYSBUFF for new R/3 installations is 1024.

PhysLog Written/IO should be at least 75 % of PhysLog Buf. Otherwise, we recommend you to change the parameter PHYSBUFF and watch the change in PhysLog Written/IO.

You can check whether the current value of PHYSBUFF is sufficient for your system on the main screen of the database monitor, by looking in the section Log Buffers. Or you can use the command onstat –l , as in the following example: