How to configure Kaio when installing Informix on HP Platform

Anyone who has some experience using Informix databases knows that Informix has two Io Methods: AIO and Kaio. AIO is the traditional synchronous Io, but most Informix users do not know Kaio. Kaio is called Kernel I/O. because it uses the kernel I/O of the operating system, Io reads and writes faster than AIO, which improves the efficiency of the Informix database as a whole.

In file I/O synchronization, the thread starts an I/O operation and immediately enters the waiting state until the I/O operation is complete. In asynchronous file I/O mode, the thread sends an I/O Request to the kernel and continues to process other things. After the kernel completes the I/O request, it will notify the thread that the I/O operation is completed.

Kaio (kernel asyncronous I/O) is a feature of Informix, which is supported by most platforms. On the AIX and Sun platforms, This is the default setting. After the database is successfully installed, there will be a Kaio thread. On the HP platform, to configure Kaio, You need to modify the operating system environment and set kaioon, the procedure is as follows:

1) Your platform supports this function (check the content in $ informixdir/release to see if your platform supports Kaio)

2) You are using a bare partition (root =/dev/vg01/rrootdbs)

1. Disable online and modify Informix Environment Variables
Export ifmx_hpkaio_num_req = 2300
Export kaioon = 1

2. Operating System Device (11.23 not required)
Add the asyncdsk device to the kernel drive of the minicomputer. After restructuring the operating system, restart the system.
Log on to Sam, set asyncdsk to in, rebuild the operating system, and restart the system.

3. confirm that the/dev/async device is generated in the minicomputer/dev directory.

If you do not have an asyncdsk device, use the following method to generate

1) Su Root
2) #/usr/sbin/mknod/dev/async C 101 0
3) # chmod 0666/dev/async

4. Set Kaio Device Permissions

1) Create the/etc/privgroup File
# Touch/etc/privgroup

2) Add the mlock privilege to the Informix User Group
# Vi/etc/privgroup
Informix mlock

3) use the setprivgrp command to set the new privilege
# Setprivgrp-F/etc/privgroup

4) run the getprivgrp command to verify that the new privilege is in place
# Getprivgrp
Global privileges: chown
Informix: mlock

5. Restart the database
Oninit-V

6. Verify if the Kaio clue appears
Check online. log or onstat-G ath to confirm Kaio takes effect.
If Kaio takes effect, the following information should be contained in the message file of Informix:

11:18:23 HPUX version B .11.11-> using flag/Select style. Kaio
11:18:23 HP Kaio concurrent requests changed from 1000 to 2300