RE: I/O Performance/bottlenecks on EMC Symmetrix

From: Koivu, Lisa <lisa.koivu_at_efairfield.com>
Date: Thu, 13 Sep 2001 09:53:50 -0700
Message-ID: <F001.0038D3E2.20010913074520@fatcity.com>

John, I have to say that's a very interesting post. Two shops I've worked in utilizing an EMC Symmetrix claimed that there's no way you could ever end up with i/o problems and you shouldn't even consider it when creating a database on these disks. All conventional knowledge was out the window (tables & indexes on separate disks, etc., etc.) I couldn't get by it, I just didn't believe it (like trying to convince myself of physics topics that just didn't make sense - "just tell yourself it's true"). You validated my gut feel.

Thanks for sending this.

Lisa Koivu
Oracle Database Administrator
Fairfield Resorts, Inc.
954-935-4117

-----Original Message-----

From:   Hallas John [SMTP:John.Hallas_at_btcellnet.net]
Sent:   Thursday, September 13, 2001 10:01 AM
To:     Multiple recipients of list ORACLE-L

Subject: RE: I/O Performance/bottlenecks on EMC Symmetrix

At one site I worked using Oracle Financials we were having serious performance problems at what seemed to us random intervals. Spent months looking at the database after the Unix boys had said that there was no way we could have I/O problems with the throughput capabililities of EMC and the Symetrix set up we had.

Eventually turned out that 3 systems were sharing the same disks and the disks had not been striped. Therefore other system were causing us performance problems.

If you have an EMC support contract which I think you must have you, the SA's get all the free GUI tools that allow them to look at channels and logical/physical layout. Ask them about.

John

-----Original Message-----

From: nlzanen1_at_EY.NL [ <mailto:nlzanen1_at_EY.NL>] Sent: 13 September 01 12:55
To: Multiple recipients of list ORACLE-L Subject: I/O Performance/bottlenecks on EMC Symmetrix

!! 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

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Received on Thu Sep 13 2001 - 11:53:50 CDT