Re: Disk Async IO
- From: BN <bnsarma@xxxxxxxxx>
- To: dbvision@xxxxxxxxxxxx
- Date: Fri, 8 Sep 2006 09:28:55 -0400
On 9/7/06, Nuno Souto <dbvision@xxxxxxxxxxxx> wrote:
BN wrote,on my timestamp of 7/09/2006 4:54 AM:
> I remember reading Oracle Metalink Notes saying that Disk Async IO is > not supported on HP-UX for Cooked Filesystems.
er... you're correct in the Metalink references. But there is no such thing as "cooked filesystems". There is "raw" IO and "cooked" IO: the first is *without* filesystems, the second *with* filesystems.
> We have disk_async_io=true for our Database in HP-UX 11.11 , Oracle > 22.214.171.124 <http://126.96.36.199> and 10g Servers.
won't do a thing for you unless you're using raw database files - with no file system associated, just the device name used as datafile name in Oracle.
> Right now we are using 4 dbwr's. I appreciate your suggestions.
Keep using the 4 dbwrs and lose the disk_async_io parameter: it's doing nothing unless you're using raw IO.
> Our UNIX SA says " Cooked Filesystems have their own Asynchronous > Mechanisim that equally replaces Oracle Async IO"
I'll add my voice to Kevin's reply...
> What Am I missing here
A lot. To get aio in filesystems in HPUX you must use a filesystem type that supports it. As of last time I checked it, the only one that did in HP environments was vxfs, the Veritas file system for HP. None of the native HPUX ones did. Oh: did I mention that vxfs is an extra? As in: "mucho dinero"?
-- Cheers Nuno Souto in sunny Sydney, Australia dbvision@xxxxxxxxxxxx -- http://www.freelists.org/webpage/oracle-l
Thank you for the info.
You mean if The Filesystems are created/mounted using vxfs, then we can use Async IO on HP-UX?
-- Regards & Thanks BN