Asynchronous i/o for file devices?

[Tina Waitherwerch]

I am installing sybase ASE12.5 on HP-D380 11i. I created database device files as raw, except for one device - which I left as a file device. I set asyncdisk to In from SAM, did a mknod for /dev/async, then chmod then chown. But when I bring up sybase, the errorlog says:
kernel Initializing virtualdevice'/dev/vg01/master_dev' with dsync 'on'.
kernel Virtual device 0 started using standard unix i/o.

Can file devices use Async I/O? Or have I missed a step setting it up?

Thanks

[Vijeesh CTK]

Hi

hi i would like to know what is the one device which is file device.

If the master device is (virtual device 0) is a file device ( ie block device) the sybase will come up with Standard Unix IO bcoz for all file devices sybase uses Standard IO.

Regards

CTK

[Vijeesh CTK]

hi again

what u do is make the master device as /dev/vg01/rmaster_dev( raw device) and recreate database.

One more thing you have to do is

# setprivgrp "sybase group" MLOCK

and start the server


CTK

[Tina Waitherwerch]

As a matter of fact it is device 0(master device). However upon further investigation of the errorlog, all the devices(raw and file)say they will be using standard UNIX i/o. How can I verify after SAM that I have async set up correct?

[Vijeesh CTK]

hi

when ur master device itself is file device there is no way in sybase to make database device to make up in Aysnc IO mode.

what u can do is make another device in vg01 like
/dev/vg01/rlvmasterdev(raw device) of same size and make it a mirror copy of /dev/vg01/master_dev in sybase, and use unmirror command in sybase and make the secondery device as primary

or if ur setup is fresh just recreate the database with raw device ( /dev/vg01/rmaster_dev)

CTK

[Vijeesh CTK · Accepted solution]

hi


just check you config value

1> sp_configure 'allow sql server async i/o'
2>
Parameter Name Default Memory Used Config Value
Run Value
------------------------------ ----------- ----------- ------------
-----------
allow sql server async i/o 1 0 1
1



CTK

[Tina Waitherwerch]

Thank you for the quick response. THis turns out that this was a Sybase problem, but you still gave me the answer in a round-about way. Sure, I had done everything correctly on the HP side, but I had forgotten to set up async i/o on the Sybase side. Once I checked the sp_configure command. I was able to turn it on and now all my file and raw devices use asynchronous i/o. Thanks