Re: direct path write wait

Hi All,

"Have read in an article that the DB may need to use asynchronous IO for log 
files and temp files and direct IO for data files". 

Have few queries on this w.r.t. Solaris 9 (Oracle 9.2.0.7) 

> Can both asynchronous IO and direct IO be enabled on the OS file system at 
> the same time? 

> If yes, what if we have mounted the file system using "forcedirectio" option? 
> Can the database still use both modes of IO? 

> How to enable both the IO modes? What are the parameter settings for the 
> same? 

Regards,

Deepak
  ----- Original Message ----- 
  From: LS Cheng 
  To: deepak_blr@xxxxxxxxxxx 
  Cc: ORACLE-L 
  Sent: Wednesday, December 27, 2006 9:03 PM
  Subject: Re: direct path write wait


  Hi

  You can truss database writer, if AIO is enabled you should see something like

  kaio(AIONOTIFY, -2226439408)       
  kaio(AIOWAIT, 0xFFFFFFFF7FFFDFA0)  




  On 12/27/06, blr_dba <deepak_blr@xxxxxxxxxxx> wrote:
    Dear Gurus,

    Am having huge amount of waits on "direct path write event". This event has
    98% of the total wait time. Now we want to tune it.

    We are using Solaris 9 and Oracle 9.2.0.7.

    After examining the system we found that logging is enabled on the mounted
    UFS file systems.

    Need your expert advice on the following...

    > How to know whether the UFS is enabled for asynchronous IO or direct IO? 
    > Which one is better for DWH environments? Pros and cons of each.
    > Is filesystem cache is involved in both of the above methods?

    Please suggest the best solution for my environment.

    Looking forward to your ever valuable feedback. 

    Deepak

    --
    http://www.freelists.org/webpage/oracle-l

Other related posts: