RE: Solaris-Single node Vs Linux 3 nodes RAC
- From: "Jorgensen, Finn" <Finn.Jorgensen@xxxxxxxxxxxxxxxxx>
- To: "frits.hoogland@xxxxxxxxx" <frits.hoogland@xxxxxxxxx>, "sgnanap@xxxxxxxxx" <sgnanap@xxxxxxxxx>
- Date: Mon, 5 Nov 2012 18:02:54 -0500
Veritas inherently does not do DIO unless you've implemented ODM/Quick IO which
is unlikely. That means buffered IO. I've personally seen what a huge
difference it can make when the OS has buffered the data already. It's very
possible this is the reason for the difference.
Thanks,
Finn
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Frits Hoogland
Sent: Monday, November 05, 2012 11:43 AM
To: sgnanap@xxxxxxxxx
Cc: oracle-l
Subject: Re: Solaris-Single node Vs Linux 3 nodes RAC
Please use a sql trace at level 8 to understand what oracle is doing in both
cases.
ASM is inherently DIO thus no buffering. If the database on Solaris does not do
DIO, and there is much memory free, there is a chance the OS buffers the IO's
Frits Hoogland
http://fritshoogland.wordpress.com
frits.hoogland@xxxxxxxxx
+31 6 53569942 <+31%206%2053569942>
Op 5 nov. 2012 om 16:44 heeft Sudhakar G Pillai <sgnanap@xxxxxxxxx> het
volgende geschreven:
All,
I appreciate if you could shed some light on which direction to go. I have
Solaris non-rac database running with 26GB SGA ( PDB-NONRAC(Solaris)) and
3 node RAC database in Linux with 100GB SGA ( PDB-RAC ) . One of our program
runs 3 times slower on RAC vs Soalris. Same SQL code , same plan, and same
oracle version etc. Solaris has file system with Veritas LVM and Linux has ASM.
Here is the output of 10046:
SQL ID: 9txtqr9tdkcbs
Event waited on Times Max. Wait Total
Waited
---------------------------------------- Waited ---------- ------------
PDB-NONRAC(Solaris) db file sequential
read 413468 0.32 234.99
PDB-RAC(LINUX) db file sequential
read 434173 0.50 2138.24
Is it Veritas's LVM caching playing the role here vs no-caching in ASM?
Thank you,
Sudhakar G Pillai
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