AIX lrud process on Oracle db server
DB - Oracle 11g/10g OS - AIX 6.1/5.3 When running oracle on AIX, one issue that can occur is high CPU with os process lrud using large % of the available CPU and large Kernel cpu usage as well. This will cause the instance to hang with errors such as 'ORA-00020: maximum number of processes exceeded' . Topas output on this situation can be similar to bellow, lrud is the page stealing process used by AIX virtual memory manager. So this shows a situation where OS VMM is heavily active. Below lists some checkpoints from both Oracle and OS end for this issue. From Oracle --> When oracle is not using Direct I/O which means OS level caching is not used the OS VMM will be freed from all the overhead due to oracle I/O activity. So using Direct I/O with large SGA can be a solution. The parameter 'filesystemio_options' defines the method oracle uses for I/O. By setting SETALL for this parameter we can enable Direct I/O from db end. From AIX --> Some...