RE: linux Async io

  • From: "Hsieh, Joan" <Joan.Hsieh@xxxxxxxxx>
  • To: Frits Hoogland <frits.hoogland@xxxxxxxxx>
  • Date: Fri, 22 Mar 2013 20:38:14 +0000

I'm happy to do so. So far I have run awr reports on both servers. I'll work on 
it .

Thanks in advance,
Joan

-----Original Message-----
From: Frits Hoogland [mailto:frits.hoogland@xxxxxxxxx] 
Sent: Friday, March 22, 2013 4:08 PM
To: Hsieh, Joan
Cc: Mark W. Farnham; david.barbour1@xxxxxxxxx; oracle_l
Subject: Re: linux Async io

Can you trace in both sides and run both results through orasrp?
It'll give you an overview over the waits and give wait histograms.

Frits Hoogland

http://fritshoogland.wordpress.com
frits.hoogland@xxxxxxxxx
+31 6 53569942

(Sent from my iPhone, typo's are expected)


Op 22 mrt. 2013 om 21:01 heeft "Hsieh, Joan" <Joan.Hsieh@xxxxxxxxx> het 
volgende geschreven:

> Thanks Mark,
>
> I'm curious the sync setting, but we are actually experiencing the 
> performance issue, 60% of wait time is user io, db_ sequential_read is on top 
> of it. This is a show stopper for us,  and I am trying to find out the cause.
>
> Joan
>
> -----Original Message-----
> From: Mark W. Farnham [mailto:mwf@xxxxxxxx]
> Sent: Friday, March 22, 2013 2:52 PM
> To: Hsieh, Joan; 'Frits Hoogland'; david.barbour1@xxxxxxxxx
> Cc: 'oracle_l'
> Subject: RE: linux Async io
>
> Frits' suggestion was to sql_trace at level 8, presumably to see whether 
> you're getting actual async i/o and the details of i/o requests, as opposed 
> to just whether your execution plan changed. While changes to your plans may 
> indeed be of critical interest, the thread title is about async io.
>
> mwf
>
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx 
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
> On Behalf Of Hsieh, Joan
> Sent: Friday, March 22, 2013 2:39 PM
> To: Frits Hoogland; david.barbour1@xxxxxxxxx
> Cc: oracle_l
> Subject: RE: linux Async io
>
> Thanks Frits,
> I have compared the execution plans, they both are same.  I created the new 
> database on Linux and using datapump import the data from the source.  The 
> parameter are not much different, the memory_target set to 1000m on Linux, we 
> use sga_target on Aix which is 700mb.  The db_file_multiblock_read_count on 
> AIX,  it is 128 on Linux ( auto set).
>
> Joan
>
> From: Frits Hoogland [mailto:frits.hoogland@xxxxxxxxx]
> Sent: Friday, March 22, 2013 2:07 PM
> To: david.barbour1@xxxxxxxxx
> Cc: Hsieh, Joan; oracle_l
> Subject: Re: linux Async io
>
> A sane beginning would be to start with source platform and version and 
> hardware layout en destination specifications. And parameters of both 
> instances.
>
> Then look at both (source and destionation) execution plans.
>
> Then run the critical sql's on both platforms with SQL trace at level 8, and 
> compare them.
>
> Frits Hoogland
>
> http://fritshoogland.wordpress.com<http://fritshoogland.wordpress.com/
> > frits.hoogland@xxxxxxxxx<mailto:frits.hoogland@xxxxxxxxx>
> +31 6 53569942<tel:+31%206%2053569942>
>
> Op 22 mrt. 2013 om 18:55 heeft David Barbour 
> <david.barbour1@xxxxxxxxx<mailto:david.barbour1@xxxxxxxxx>> het 
> volgende
> geschreven:
> Joan,
>
> It appears it is - but may not be very efficient at this point.  What version 
> of Oracle and Linux are you using?  What type of filesystem/disk/etc. (Not 
> just NetApps - ASM, OCFS, etc.)?
>
> On Fri, Mar 22, 2013 at 11:47 AM, Hsieh, Joan 
> <Joan.Hsieh@xxxxxxxxx<mailto:Joan.Hsieh@xxxxxxxxx>> wrote:
>
> Hi,
> We are migrating DW database from AIX to linux, the online transaction is ok 
> compared to AIX. But the batch job is 35% slower  than AIX.  Of course, the 
> architecture are different, the storage is Netapps on Linux. From the awa 
> report. 60% time is user IO waiting.  I'm not sure how to read the following 
> information, is it async io enabled?
>
> Thank,
>
> Joan
>
> dwdb-prod-01:c0ra1e)SDWPRD:/oracle/product/11.2.0.3/bin<http://11.2.0.
> 3/bin>
>> cat /proc/slabinfo | grep kio
> kioctx                56     80    384   10    1 : tunables   54   27    8 :
> slabdata      8      8      0
> kiocb                  0      0    256   15    1 : tunables  120   60    8 :
> slabdata      0      0      0
> dwdb-prod-01:c0ra1e)SDWPRD:/oracle/product/11.2.0.3/<http://11.2.0.3/>
>
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