!! Please do not post Off Topic to this List !!
WOW! Is the "other" workload on these similar when this job runs? Are you sure
the problem is the Symmetrix and not something in the OS or instance
configuration? Does this job spend a lot of time waiting (in Oracle) on physical
I/O - or on something else? (I guess if you don't have access to the machine,
you can't find out though. The ultimate tuning challenge!)
If the problem is actually Symmetrix I/O, I could only hazard a guess that it
might be due to RAID-5 for something inappropriate (hot redo log files?) or
extreme I/O contention in the layout.
As far as pointers, pitfalls, and suggestions... I really have only one: don't
believe everything you hear!
For example: (top 10 list)
1) "With EMC, RAID-5 won't matter." (it likely still will - for write-intensive
stuff)
2) "With EMC, you don't want to stripe." (you might - it can still make a big
difference)
3) "With the cache, I/O won't ever be a bottleneck." (until cache becomes
saturated or ...)
4) [Corollary to #3] "Throw out all that basic I/O tuning stuff you learned"
(but back it up to tape first!)
5) "The best layout is always SAME - stripe and mirror everything across
everything."
6) "The check is in the mail."
7) "This won't hurt a bit."
[ORA-00051]
Drat! I crashed before getting to ten! Sorry, I was up all night repairing a
bridge...
For more serious and less evasive answers, see Gaja's paper at
http://www.quest.com/whitepapers/Raid1.pdf
-Don Granaman
[OraSaurus - Honk if you remember UFI!]
----- Original Message -----
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
Sent: Thursday, September 13, 2001 6:55 AM
!! Please do not post Off Topic to this List !!
Hi All,
Does anybody here on the list have experience with EMC/symmetrix storage
units.?
We have our databases on this machine and I have a feeling the the I/O
performance is not very good. I can not proof it since I do not have any
experience/data/access to that machine. We do however have a very
cooperative UNIX group but they also lack experience with performance on
this machine.
Who can give me pointers about I/O throughput that can be reached,
configuration pittfalls etc..
Example:
RS6000 8CPU's and 4Gb memory with storage on EMC/symmetrix. Job takes about
2 hours to complete.
F50 1 CPU 1Gb memory (TEST machine) local disks. same job takes 0.5 hours
to complete.
Jack
=====================================================================
De informatie verzonden in dit e-mailbericht is vertrouwelijk en is
uitsluitend bestemd voor de geadresseerde. Openbaarmaking,
vermenigvuldiging, verspreiding en/of verstrekking van deze informatie aan
derden is, behoudens voorafgaande schriftelijke toestemming van Ernst &
Young, niet toegestaan. Ernst & Young staat niet in voor de juiste en
volledige overbrenging van de inhoud van een verzonden e-mailbericht, noch
voor tijdige ontvangst daarvan. Ernst & Young kan niet garanderen dat een
verzonden e-mailbericht vrij is van virussen, noch dat e-mailberichten
worden overgebracht zonder inbreuk of tussenkomst van onbevoegde derden.
Indien bovenstaand e-mailbericht niet aan u is gericht, verzoeken wij u
vriendelijk doch dringend het e-mailbericht te retourneren aan de verzender
en het origineel en eventuele kopieën te verwijderen en te vernietigen.
Ernst & Young hanteert bij de uitoefening van haar werkzaamheden algemene
voorwaarden, waarin een beperking van aansprakelijkheid is opgenomen. De
algemene voorwaarden worden u op verzoek kosteloos toegezonden.
=====================================================================
The information contained in this communication is confidential and is
intended solely for the use of the individual or entity to whom it is
addressed. You should not copy, disclose or distribute this communication
without the authority of Ernst & Young. Ernst & Young is neither liable for
the proper and complete transmission of the information contained in this
communication nor for any delay in its receipt. Ernst & Young does not
guarantee that the integrity of this communication has been maintained nor
that the communication is free of viruses, interceptions or interference.
If you are not the intended recipient of this communication please return
the communication to the sender and delete and destroy all copies.
In carrying out its engagements, Ernst & Young applies general terms and
conditions, which contain a clause that limits its liability. A copy of
these terms and conditions is available on request free of charge.
=====================================================================
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author:
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Don Granaman
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
