Re: Disk Async IO

  • From: Nuno Souto <dbvision@xxxxxxxxxxxx>
  • Date: Thu, 07 Sep 2006 20:29:58 +1000

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 <> 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 -- //

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