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RE: I/O Performance/bottlenecks on EMC Symmetrix

From: Loughmiller, Greg <>
Date: Thu, 13 Sep 2001 07:26:53 -0700
Message-ID: <>

We saw
this at a previous location and we found that we had logical volumes on the same disk.. Used for different applications, and even different systems!!† For example-someone placed TEMP for DB1 and TEMP for DB2 on the same disk unknowingly....† This created just a small contention problem...

is a common problem when large sym cabinets are set up with "logical volumes split to different systems".<FONT
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LV may be defined such that you wont know that they are on the same disk.† If you are using BCV's, and clustering-it get's even more detailed and confusing...
<FONT face=Arial color=#0000ff
the EMC rep come in, take a look at the "bin" file of your sym cabinet(s).. And see where the logical volumes are living..† Draw a map of the bin file with a graphical representation of each LV, and where they live...
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  size=2>-----Original Message-----From: Hallas John   []Sent: Thursday, September 13,   2001 10:01 AMTo: Multiple recipients of list   ORACLE-LSubject: 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 [<A
  href="mailto:nlzanen1_at_EY.NL">mailto:nlzanen1_at_EY.NL] <FONT   size=2>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 <FONT   size=2>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.

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Received on Thu Sep 13 2001 - 09:26:53 CDT

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