Oracle 8i Hp-UX Vertias Quick IO and async writes

[Reach Managed Service]

How do I tell if Oracle is using Async writes?

I have a database which uses vertias async devices using Quick IO. The quick IO allows use of cooked files and file systems. The devices have been created using the usual qio admin utility and then the tablespaces are created from those files.

The database and kernel parameters have been setup as per instructions.

A truss on the DBWR process shows the usual write and read but no kaio sys calls.

qiostat is giving very strange readings in the millions if read/writes for the files and fuser doesn't show any process having a hold on the qio files.

So how can I determine whether there is actually any async io?

Thanks,
Michael.

[Zygmunt Krawczyk]

Hi Michael,

read the doc:
"Best practices for Oracle on HP-UX"
http://h21007.www2.hp.com/dspp/files/unprotected/database/HP3KOracle.ppt

Regards,
Zygmunt

[Eric Antunes]

Hi Michael,

You need raw devices to use async I/O.

Best Regards,

Eric

[Reach Managed Service]

Hi Eric and Zygmunt,
Thanks for your replies.

Zygmunt, as mentioned above in my original question the database and kernel parameters have already been setup.

Eric, Quick IO from Veritas allows async on cooked devices. That is its purpose.

Again, the big question is I have everything setup to use Async IO but nothing in Truss of the database processes points to actual async IO (i.e. no evidence of kaio just write or read). How can I categorically determine whether Async IO is active?

Thanks
Michael.

[Steven E. Protter]

Raw devices are not required to use async io.

Oracle 8.1.5 and above use async i/o by default. There are a few steps to making it work right on HP-UX, but thats in the best practices document.

SEP

[Reach Managed Service]

Hi SEP,
Thanks for your response. Do you know of a method such as qiostat or truss that could identify async io is taking part or does truss on hp-ux only report read , write and not make distinctions about async io?

Thanks,
Michael.

[Reach Managed Service]

Everyone,
Thanks for your responses but I found the answer else where.
Regards,
Michael.

[Gunnar Rønning_1]

Could you please share with us where you found the answer ? I believe we are suffering with some similar problems. What are your mount options for the filesystem ?