RE: Linux 2.6 I/O Scheduler & ASM/Raw
- From: "Kevin Closson" <kevinc@xxxxxxxxxxxxx>
- To: "Oracle Mailing List" <ORACLE-L@xxxxxxxxxxxxx>
- Date: Thu, 20 Oct 2005 20:14:31 -0700
how do you suppose a linux process is going to perform I/O
without a system call? ASM I/O is either simply libC, LibODM or
ASMlib on Linux (which is still implemented in Kernel mode).
yes yes, I know about that goofy DAFS stuff that never saw
the light of day.
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Murching, Bob
Sent: Thursday, October 20, 2005 5:46 PM
To: 'Oracle Mailing List'
Subject: Linux 2.6 I/O Scheduler & ASM/Raw
Apologies in advance for the simple question but if a database
uses raw or ASM storage, is it bypassing the operating system's I/O
layer, or not? For example, should the choice of scheduler (cfq, as,
noop, deadline) in the Linux 2.6 affect performance of an ASM or RAW
filesystem, or should it not? Likewise, are variables such as the
maximum I/O size at an OS level (e.g. 512KB or 1M) and the OS block size
(8KB, 16KB, ...) still meaningful with raw filesystems?
I suspect the answer to both questions is "yes" but I'm not sure
and haven't seen this spelled out clearly....
Bob
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