Tuning HP-UX
To achieve optimal performance using Quick I/O, certain HP-UX parameters need to be tuned. Changing these parameters requires modifying the HP-UX kernel settings, rebuilding the kernel, and rebooting the system. See the HP-UX System Administration Tasks manual for the detailed procedure on how to reconfigure the HP-UX kernel. If you use SAM, the HP-UX system administration utility, to rebuild your kernel, make sure the Overwrite /stand/system button on the Reboot the System dialog menu is selected. The rest of this section describes the important tuning parameters.
Note
The settings for all tunable parameters depend on such factors as the size of your system and database, the database load, and the number of users. In some cases we make suggestions for setting the parameters; however, you should always consult the Oracle Installation Guide for your system and version, and use the settings recommended by Oracle when provided.
max_thread_proc
This parameter sets the maximum number of threads that a process can create. The high performance of VxFS and the Quick I/O driver depend on the value of this tunable. Set the max_thread_proc parameter to 1200.
asyncdsk, asyncdsk_included, and max_async_ports
These parameters are used for including and configuring the asynchronous I/O driver in the HP-UX kernel, resulting in less I/O overhead and higher throughput. The parameter max_async_ports sets the maximum number of connections between user processes and the asyncdsk driver. See your Oracle documentation for the recommended value, or set max_async_ports to 1024 if a value is not recommended.
eqmemsize
The I/O subsystem uses a pool of memory allocated by the eqmemsize parameter for I/O system memory. The eqmemsize parameter specifies the minimum amount of this equivalently mapped memory. The exhaustion of this memory pool degrades I/O performance, thus impacting application performance. See your Oracle documentation for the recommended value, or set eqmemsize to 512 if a value is not recommended.
nproc
This parameter sets the maximum number of processes. The nproc parameter may need to be set higher for a large database. See your HP-UX and Oracle documentation for the recommended value.
maxuproc
This parameter sets the maximum number of processes a non-root user can create in parallel. The maxuproc parameter may need to be set higher for a large database. See your HP-UX and Oracle documentation for the recommended value.
semmni
This parameter sets the number of semaphore set identifiers in the system. The semmni parameter determines the number of semaphore sets that can be created at any one time, and may need to be set higher for a large database. See your HP-UX and Oracle documentation for the recommended value.
semmns
This parameter sets the maximum number of semaphores in the system. The semmns parameter may need to be set higher for a large database. See your HP-UX and Oracle documentation for the recommended value.
|
