728x90
Problem(Abstract)
This article goes over the environment variable that can be used to change the default resources used by the engine for Kernel Asynchronous I/O (KAIO) on the HP-UX platform.
Resolving the problem
PROBLEM
Database performance is poor because of input/output (I/O) requests. The IBM® Informix® Dynamic Server™ message log might display one of these error messages:
- KAIO out of OS resources, errno = 11
or
- KAIO out of OS resources, errno = 35
CAUSE
Each time the database server makes a kernel asynchronous input output (KAIO) request, it uses a special operating system structure. A certain number of these structures are allocated when the database server starts and are reused as long the instance is online.
The problem will occur if there are not enough structures available to handle all of the I/O requests made by the database server.
Note: This is only one possible cause for this problem. If this document does not solve your problem, see if other documents exist for the same problem.
SOLUTION
Increase the number of KAIO requests allowed simultaneously by the database server. Do this by increasing the value of the IFMX_HPKAIO_NUM_REQ environment variable.
Set the variable to the desired number at the command line and then shut down and restart the database server.
Limits of the IFMX_HPKAIO_NUM_REQ environment variable. | |
Minimum Value | 10 |
Maximum Value | 5000 |
Default Value | 1000 |
Note: These values may change in future versions of the operating system or database server.
- Example:
- This example shows how to increase the number of concurrent KAIO requests to 2300 from the default of 1000 using Korn shell:
- $ IFMX_HPKAIO_NUM_REQ=2300
$ export IFMX_HPKAIO_NUM_REQ
You can also change some operating system kernel parameters for KAIO. If you are still experiencing poor performance, contact your local technical support office.
http://www-01.ibm.com/support/docview.wss?rs=0&uid=swg21142285
728x90