Re: HP-UX Kernel AIO

Sean Kelsey wrote: > > Informix 7.24.UC5 on HP-UX 11 > > We hope to implement Kernel AIO on our HP/800 box running HP-UX 11 but have > a few questions. The ONLINE_7.2 documentation says that KAIO is available > but mentions patches that appear to be for version 10.01 & 10.10. The > ONLINE_7.2 document says:- > > =============================== > Kernel Asynchronous I/O (KAIO) is supported on this platform. However, it > is DISABLED by default. To enable KAIO set the environment variable > KAIOON. It is only effective on raw partitions. > > KAIOON=1; export KAIOON (for Bourne or Korn Shell) > > setenv KAIOON 1 (for C Shell) > > The following is a pre-requisite for using KAIO: > > o. HP KAIO driver "asyncdsk" is installed and linked into the > kernel. > > o. To ensure KAIO driver is up and running, check to see if there > is /dev/async, if not follow these steps: > > 1) su root > 2) /usr/sbin/mknod /dev/async c 101 1 > 3) chmod 0666 /dev/async > > To improve the performance of the server, the KAIO interface is > modified in this version of OnLine. It is suggested to have the > following patches installed on the system. > > 10.01/700 PHKL_6660 Select System Call performance patch > 10.01/800 PHKL_6661 Select System Call performance patch > 10.10/700 PHKL_6662 Select System Call performance patch > 10.10/800 PHKL_6663 Select System Call performance patch > > An environment variable IFMX_HPKAIO_NUM_REQ is provided to specify > the number of simultaneous KAIO requests that are processed by the > server at one time. The value can be set in the range of 10 to 5000, > the default being 1000. If the error > > "KAIO: out of OS resources, errno = %d, pid = %d" occurs, > consider increasing the value of IFMX_HPKAIO_NUM_REQ. > > IFMX_HPKAIO_NUM_REQ=2300; export IFMX_HPKAIO_NUM_REQ > (for Bourne or Korn Shell) > > setenv IFMX_HPKAIO_NUM_REQ 2300 (for C Shell) > ===================== > > My questions are:- > > 1. Will the above async procedures configure the HP KAIO driver correctly ?? Sounds about right. > 2. Do these patches still need to be applied ( even though they look like > patches for 10.01 and 10.10 ) and if not, are there 11.x equivalents ?? Yes. You might want to check with Informix for an additional patch list, just in case. > 3. What recommended settings should I use for the IFMX_HPKAIO_NUM_REQ > parameter so that I don't run out of KAIO OS resource ( we have 36 raw > partitions )?? We didn't . . . if there's a problem, you'll see the message in online.log. > 4. Will I need to bounce the server as well as the engine ?? We bounced the engine only with 7.13. > 5. When ( and where ) do I need to set the KAIOON parameter ?? Informix startup script, before the oninit, of course. You might want to check with Informix concerning bug 92132. It was fixed in 7.30, but as far as I know there has been no request to backport it to 7.24. It really caused a problem in 7.23 (where we are currently); we're upgrading soon to be able to utilize it once again. John Carlson Informix DBA WHSmith USA