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Re: Async_io set up HP-UX for 10g Instances(these are apps instances)

From: LS Cheng <exriscer_at_gmail.com>
Date: Mon, 6 Aug 2007 17:19:08 +0200
Message-ID: <6e9345580708060819x2a1467d3pf88c08bc5edc5267@mail.gmail.com>


Dude we all have told you you cannot use AIO with Filesystems!

If you really really want to use AIO with Filesystems then buy Veritas Quick I/O. That does support AIO with Filesystem but using Cluster Filesystems.

Thanks

--
LSC


On 8/6/07, edwin devadanam <edwin_kodamala_at_yahoo.com> wrote:

>
> Hi All,
>
> Please add ur valuable comments on the below mentioned points.
>
> This is production database:
>
> SQL> show sga
> Total System Global Area 3215950016 bytes
> Fixed Size 741568 bytes
> Variable Size 1056964608 bytes
> Database Buffers 2147483648 bytes
> Redo Buffers 10760192 bytes
>
> 1) As discussed we can't use disk_asynch_io=true in HP-UX(its using jfs
> not raw filesystem)
> 2) Is HP-UX(JFS) doesnt suport asynchronous io?(operating system level)
> 3) dbwr_io_slaves=x or db_writer_processes=y which one does asynchronous
> i/o?(refer Note:47328.1)
> 4)Keeping db_writer_processes=y only will i not achieve asynchornous i/o?
>
> Thanks In Advance,
> Edwin.K
>
> *Roby Sherman <rxsherm_at_interealm.com>* wrote:
>
> >
> > - disk_asynch_io is used to enable the oracle kernel to make use of
> > asynchronous io, IF the OS supports it.
>
> And you really DO want to figure out if your OS supports it.
> Otherwise if you turn it on and its not supported, your database is
> essentially making two I/O calls for every one... One to aio_write
> (which fails) and then an immediate call to pwrite after. I can't
> tell you how many environments I come into where disk_asynch_io is
> set to true and it isn't supported.
>
> --Roby
> --
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>
>
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Received on Mon Aug 06 2007 - 10:19:08 CDT

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