topic Re: async I/O in Operating System - HP-UX

async I/O

Sid Bytheway — Tue, 20 Feb 2001 17:43:19 GMT

My /dev/async is missing on HPUX 11, we cannot start oracle 8.0.4. What is the procedure for creating this device, it must be more than running mknod, because I ran that and we are still having problems.

Re: async I/O

James A. Donovan — Tue, 20 Feb 2001 18:43:03 GMT

Is the value of the fs_async kernel parameter 0 or 1? If 0, set it to 1 and re-compile the kernel.

Re: async I/O

Sid Bytheway — Tue, 20 Feb 2001 18:56:58 GMT

fs_async is already set to 1. I believe this device used to exist, we have run oracle 8.0.4 prior to this without a problem. Now when we try to start it, it says, there is no /dev/async. I ran mknod to recreate it, but oracle won't start. Oracle 8.0.5 is running, however.

Re: async I/O

James A. Donovan — Tue, 20 Feb 2001 19:19:26 GMT

Ok, since you have fs_async set, then try the following to re-create the device:

#mknod /dev/async c 101 0x000000
#chown oracle:dba /dev/async
#chmod o-rw /dev/async

If that fails, try checking for OS patches involving asynch i/o.

Is there a specific error message given in the databases alert_log? What are the init.ora parameters for your database?

Re: async I/O

Rammig Claus — Wed, 01 Jan 2003 18:06:30 GMT

Hi Cliff,

fs_async is only for HFS-Filesystem.

If you want to enable async io, you need:
- /dev/async device
- async-io driver in the kernel
- MLOCK-Privileg

Regards
Claus