RE: aio on sun ufs problem

  • From: "David Green" <thump@xxxxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 4 May 2004 22:27:47 -0500

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx =
On Behalf Of zhu chao
Sent: Tuesday, May 04, 2004 5:00 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: aio on sun ufs problem

Hi friends:
    While reading the following paper:
    It says for oracle 8.1.7/ufs, aio is by default disabled. We must =
it explictly with _filesystemio_options=3Dasynch. Is it true? For aio on =
device/QuickIO, we can see truss -t kaio -p dbwr to verify it, for aio =
filesystem, how to verify it then?
Aio on solaris is enabled by default if you use disk_asynch_io =3D true. =
will see a failed system call to kaio and then pread pwrite processes =
to simulate aio via light weight threaded processing.
You can verify this in the same way using truss against dbwr.  I'm not =
what -t does, but if you just truss on dbwr process you will see the
behavior.  I personally feel that dbwr_io_slaves when weighed against =
facts are better suted at simulating aio than the light weight threaded
- David

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