Hi Boris, Thanks for your sharing, it is quite useful. I think I should also share a little thing with everyone too, please find the attached for Oracle & Sun's Exadata Server which might has a very good I/O performance on Oracle RDBMS:)
Thanks & Best Regards, Bill 2009/9/18 Boris Tsun <boris.tsun at gmail.com> > Hi Bill, > attached is a document that i reference that you might find useful. > > > regards > > Boris Tsun > > > On Fri, Sep 18, 2009 at 10:55 AM, Bill Shi <xianbiao.shi at gmail.com> wrote: > >> I agree with Nathan & Richard's opinions. >> Physical & Logical I/O related issues were, are and will always be a >> significant factor for performance tuning regarding Oracle database server, >> especially in an OLTP environment(Oracle's multi-versioning & write-ahead >> logging mechanism). >> >> Usually, I will take a look at prstat -Lmc/mpstat and iostat -xncz to find >> out what happen to specific volume or disk, and get into Oracle RDBMS by >> statspack or AWR(since 10g) for Top 5 wait events(log file sync and dbwr >> related entries would commonly be the cases that contribute large amount of >> I/O). Additionally, I/O operations caused by checkpoint actions like log >> file switch which can be reduced greatly if you can properly configure the >> fast_start_mttr_target/log_checkpoint_xxxx parameters, etc. For Oracle >> server processes contention, I suggest to take a look at Latch Free and CPU >> Parses(especially cursor Hard Parses) and so on. You can also find most of >> these information by V$ views mentioned by Richard in previous email, they >> are really helpful. Furthermore, the business model(application) would also >> be one of the factors to find out the root cause of your performance >> problem. Through my point of view, performance tuning should begin at the >> beginning of the system design phase. >> >> As Nathan said, if you can answer the questions below, many problems can >> be exposed: >> - What does the statspack say about IO latency? >> - what does iostat say about IO latency >> - what is the seat of the pants feel in doing an IO on the devices they >> are using for that instance? (Logs and data) >> - Are the devices logging any errors >> >> Good luck:) >> >> >> Thanks & Best Regards, >> >> Bill >> >> >> 2009/9/17 Alexander Box <Alexander.Box at sro.vic.gov.au> >> >>> >>> Following last night's presso from Nathan and Andre (thanks very much for >>> another interesting night) - >>> >>> Yesterday one of our DBAs was complaining about IO performance and >>> supplied two PIDs to look at from the OS. (Thanks!) >>> >>> Although vxstat/iostat on the diskgroup/associated LUNs showed a >>> consistently large number of write IOPS, response times were always low. The >>> oracle processes had >200 LWPs, and running a prstat -mL -p <PID> showed >>> that at all times, every thread bar one spent 98% of its time in LCK. >>> >>> Any speculation? >>> >>> Regards, >>> Alex >>> >>> >>> Disclaimer: The information transmitted is intended only for the person >>> or entity to which it is addressed and may contain confidential and/or >>> privileged material. Any review, retransmission, dissemination or other use >>> of, or taking of any action in reliance upon, this information by persons or >>> entities other than the intended recipient is prohibited. If you received >>> this in error, please contact the sender and delete the material from your >>> computer. >>> Privacy: If you are responding to this email or providing personal >>> information to the SRO for the purposes of one of the Acts it administers, >>> such information is used only for the purpose for which it was collected >>> (administration of SRO legislation ) and is protected by the Information >>> Privacy Act 2000 and secrecy provisions contained in legislation >>> administered by SRO. It is not disclosed otherwise than in accordance with >>> the law. If you would like a copy of the SRO Privacy Policy please refer to >>> SRO website (www.sro.vic.gov.au) or contact SRO on 13 21 61 and request >>> a copy. >>> >>> _______________________________________________ >>> ug-msosug mailing list >>> ug-msosug at opensolaris.org >>> http://mail.opensolaris.org/mailman/listinfo/ug-msosug >>> >>> >> >> _______________________________________________ >> ug-msosug mailing list >> ug-msosug at opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/ug-msosug >> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/ug-msosug/attachments/20090920/01d71995/attachment.html> -------------- next part -------------- A non-text attachment was scrubbed... Name: Oracle Unveils Exadata Version 2.pdf Type: application/pdf Size: 4363472 bytes Desc: not available URL: <http://mail.opensolaris.org/pipermail/ug-msosug/attachments/20090920/01d71995/attachment.pdf>
