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 =
[mailto: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:
http://de.sun.com/Partner/Softwarepartner/Oracle/Technik/pdf/oracle_on_su=
n.p
df
It says for oracle 8.1.7/ufs, aio is by default disabled. We must =
enable
it explictly with _filesystemio_options=3Dasynch. Is it true? For aio on =
raw
device/QuickIO, we can see truss -t kaio -p dbwr to verify it, for aio =
on
filesystem, how to verify it then?
---
Aio on solaris is enabled by default if you use disk_asynch_io =3D true. =
You
will see a failed system call to kaio and then pread pwrite processes =
spawn
to simulate aio via light weight threaded processing.
You can verify this in the same way using truss against dbwr. I'm not =
sure
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 =
these
facts are better suted at simulating aio than the light weight threaded
processes.
- David
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