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RE: asynch I/O

From: Matthew Zito <mzito_at_gridapp.com>
Date: Fri, 19 Sep 2003 07:49:40 -0800
Message-ID: <F001.005D082F.20030919074940@fatcity.com>

This is actually platform dependent. For example, if you're using UDP mounts under Linux, you can only have one request outstanding per mount. Consequently, multiple mounts can improve performance by allowing parallel operations.

A side benefit of Oracle on Netapp is WAFL, which as Dick pointed out, stands for Write Anywhere File Layout. Basically, an update to a block does not cause a disk seek and an update - the system simply goes to the first available raid stripe that's free and writes the block there, then updates the tree. Besides being rather crafty, it creates a situation where compound writes to multiple files - like a tablespace update and an index update - migrate close to each other on disk. I/O patterns "train" the filesystem structure.

To actually answer your original question, it will not make a difference on most platforms that are properly configured. What will make a difference is your network settings. Are you using Gigabit + jumbo frames?

Matt
*still pleased with how crafty WAFL is*

--
Matthew Zito
GridApp Systems
Email: mzito_at_gridapp.com
Cell: 646-220-3551
Phone: 212-358-8211 x 359
http://www.gridapp.com


> -----Original Message-----
> From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com] On
> Behalf Of Tanel Poder
> Sent: Friday, September 19, 2003 3:25 AM
> To: Multiple recipients of list ORACLE-L
> Subject: Re: asynch I/O
>
>
> Hi!
>
> You can have spread your datafiles in 1, 2, 3,4 ..100
> different directories or mount points, but the performance
> remain the same for all of them as long as all the mount
> points are striped on the same disks.
>
> If you think of mount points as different sets of disks, e.g.
> when adding a new mount point, you add more disks, then yes,
> IO performance will improve, because larger number of disks.
>
> Tanel.
>
>
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> Sent: Friday, September 19, 2003 5:09 AM
>
>
> > Could you clarify something for me? Are you saying that if I have a
> variety
> > of 'mounts' on our netapp
> >
> > say
> >
> > /mnt1
> > /mnt2
> >
> > I would not benefit by putting my datafiles on seperate ones? I
> > thought
> that
> > is where my I/O waits are coming from. Since we have all of our
> > datafiles
> in
> > the same directory?
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: Ryan
> > INET: rgaffuri_at_cox.net
> >
> > Fat City Network Services -- 858-538-5051 http://www.fatcity.com
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> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Tanel Poder
> INET: tanel.poder.003_at_mail.ee
>
> Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> San Diego, California -- Mailing list and web hosting services
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Matthew Zito INET: mzito_at_gridapp.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Received on Fri Sep 19 2003 - 10:49:40 CDT

Original text of this message

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