Re: directio performance question

On 6 Jul 2003 04:56:53 -0700, trestusler_at_hotmail.com (Max) wrote:

>WHy is an index creation taking more time with directio ?

You are posting insufficient information. forcedirectio applies to ufs filesystems only. If you have vxfs filesystems with only the *basic* edition of Veritas installed, forcedirectio will not work.
Also you should truss your process to check whether it really doesn't use forcedirectio, and check your init.ora for disk_async_io = true. If you have the parameter set to true and your disks don't support directio a truss will show you your lwp.kaio requests fail and Oracle is reverting to normal buffered io. That is a perfect reason for a system with forcedirectio erroneously set to true actually performing slower, because each io request will be processed 2 times.

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Sun Jul 06 2003 - 10:25:44 CDT