Simpler Navigation coming for Servers and Operating Systems
Coming soon: a much simpler Servers and Operating Systems section of the Community. We will combine many of the older boards, and you won't have to click through so many levels to get at the information you need. If you are looking for an older board and do not find it, check the consolidated boards, as the posts are still there.
Databases
cancel
Showing results for 
Search instead for 
Did you mean: 

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

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

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.
7 REPLIES
Zygmunt Krawczyk
Honored Contributor

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

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
Honored Contributor

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

Hi Michael,

You need raw devices to use async I/O.

Best Regards,

Eric
Each and every day is a good day to learn.

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

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
Exalted Contributor

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

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
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com

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

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.

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

Everyone,
Thanks for your responses but I found the answer else where.
Regards,
Michael.
Gunnar Rønning_1
Occasional Visitor

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

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 ?