RE: VIOC: sizing and performance - VMS

This is a discussion on RE: VIOC: sizing and performance - VMS ; What are your Cache resident memory section sizings and how much total and free physical memory? Cache and Oracle systems have their own memory structures and are not benefitted by XFC. On AIX nodes we would reduce the file cache ...

+ Reply to Thread
Results 1 to 3 of 3

Thread: RE: VIOC: sizing and performance

  1. RE: VIOC: sizing and performance

    What are your Cache resident memory section sizings and how much total and free physical memory?

    Cache and Oracle systems have their own memory structures and are not benefitted by XFC. On AIX nodes we would reduce the file cache sizing as to not take memory away from Cache memory structures.

    What software is on the tier two?

    Any Cache server page applications?

    -----Original Message-----
    From: "Ken Fairfield"
    To: "Info-VAX@Mvb.Saic.Com"
    Sent: 11/14/07 10:49 PM
    Subject: VIOC: sizing and performance

    We have a four-node VMSCluster consisting of two GS1280 "frames",
    each partitioned into two nodes. For reasons best known to the
    vendor of the primary application, Cerner Millennium, we're using
    VIOC rather than XFC file caching. The cluster is not homogeneous
    in that one node is dedicated to "non-production" versions of the
    application, one node is the production database server, and two
    nodes share the production "application server" duties (tier 2 in
    a 3-tier architecture).

    That said, the vendor is asking us to set VCC_MAXSIZE <= 256000,
    whereas we have it set to 512000 on two nodes, and 768000 on a
    third.

    Looking at SHOW MEMORY/CACHE/FULL on the three production nodes,
    I see Read Hit Rates of 58% (database node, 512000 maxsize),
    15% on app server node w/512000 maxsize, and 66% on the other app
    server node w/768000 maxsize (the non-prod node is at 256000 and
    has a hit rate of 71%).

    Question: What is the best, or at least a good, indicator of
    VIOC effectiveness? Is it the read hit rate, or something else?
    Secondly, what would one expect the effect would be of *reducing*
    VCC_MAXSIZE by 50%, or even 75% in the one case?

    I'm concerned that the vendor is making these recommendations
    without taking into consideration the actual potential performance
    impacts. Their comment reads like so:

    "Sets size for closed file cache. 256,000 is the start value.
    This should be tuned down later after full load conditions
    are studied."

    I.e., this seems like a new-installation setting, not one based on
    actual running history of over 2 years. And note that every change
    takes a downtime for Autogen then reboot .

    Thanks for any and all hints, tips, and/or personal stories. ;-)

    -Ken
    --
    Ken & Ann Fairfield
    What: Ken dot And dot Ann
    Where: Gmail dot Com

  2. Re: VIOC: sizing and performance

    My apologies for insufficient information in the post Michael is
    following-up. It was a hurried
    post last thing in the evening from home. I'm forced to use Google
    Groups from work, which
    is just a huge spam magnet if I use it for posting, but here goes
    anyway...

    On Nov 14, 9:43 pm, "Forster, Michael" wrote:
    > What are your Cache resident memory section sizings and how much total and free physical memory?


    OK, we're running VMS 7.3-2 with ECO's current as of last Spring,
    e.g., UPDATE-V0900 and friends installed.
    The systems have the 1.3 GHz CPUs. Database node is 12 CPUs and 40GB
    memory. The application
    server nodes each have 14 CPUs and 32 GB of memory. The database is
    Oracle 9.2.0.5 and we've
    got something like 23.5 GB of reserved memory for Oracle SGAs.

    Show Memory/Full lists these three nodes as having the following about
    of VIOC cache reserved, etc.:
    --------------------------------------------------------------------------------------------------------
    SYSMAN> do pipe sho mem/ful | sear sys$pipe "virtual i/o"/wind=(0,2)
    %SYSMAN-I-OUTPUT, command execution on node DBB1

    Virtual I/O Cache: Total Free In Use
    Cache Memory (MBytes) 250.00 157.10 92.89

    Granularity Hint Regions (pages): Total Free In Use
    Released
    %SYSMAN-I-OUTPUT, command execution on node APP1

    Virtual I/O Cache: Total Free In Use
    Cache Memory (MBytes) 250.00 24.14 225.85

    Granularity Hint Regions (pages): Total Free In Use
    Released
    %SYSMAN-I-OUTPUT, command execution on node APP2

    Virtual I/O Cache: Total Free In Use
    Cache Memory (MBytes) 375.00 0.00 375.00

    Granularity Hint Regions (pages): Total Free In Use
    Released
    SYSMAN>
    ----------------------------------------------------------------------------------------------------------

    Sorry, the output looks kind of funky in proportional fonts...

    >
    > Cache and Oracle systems have their own memory structures and are not benefitted by XFC.
    > On AIX nodes we would reduce the file cache sizing as to not take memory away from Cache
    > memory structures.


    Again, this is VIOC, *not* XFC*. And I'm not particularly concerned
    about the database
    node. And 250 MB is not a big hit on a 40GB machine. :-)


    > What software is on the tier two?


    Its Cerner's Millennium. Thought I said that in the previous post...

    > Any Cache server page applications?


    Sorry, I don't understand the question.

    -Ken
    --
    Ken & Ann Fairfield
    What: Ken dot And dot Ann
    Where: Gmail dot Com


  3. RE: VIOC: sizing and performance

    Sorry, I confused Cerner with Epic running on InterSystems' Cache.

    -----Original Message-----
    From: Ken.Fairfield@gmail.com [mailto:Ken.Fairfield@gmail.com]
    Sent: Thursday, November 15, 2007 10:46 AM
    To: Info-VAX@Mvb.Saic.Com
    Subject: Re: VIOC: sizing and performance

    My apologies for insufficient information in the post Michael is
    following-up. It was a hurried
    post last thing in the evening from home. I'm forced to use Google
    Groups from work, which
    is just a huge spam magnet if I use it for posting, but here goes
    anyway...

    On Nov 14, 9:43 pm, "Forster, Michael" wrote:
    > What are your Cache resident memory section sizings and how much total

    and free physical memory?

    OK, we're running VMS 7.3-2 with ECO's current as of last Spring,
    e.g., UPDATE-V0900 and friends installed.
    The systems have the 1.3 GHz CPUs. Database node is 12 CPUs and 40GB
    memory. The application
    server nodes each have 14 CPUs and 32 GB of memory. The database is
    Oracle 9.2.0.5 and we've
    got something like 23.5 GB of reserved memory for Oracle SGAs.

    Show Memory/Full lists these three nodes as having the following about
    of VIOC cache reserved, etc.:
    ------------------------------------------------------------------------
    --------------------------------
    SYSMAN> do pipe sho mem/ful | sear sys$pipe "virtual i/o"/wind=(0,2)
    %SYSMAN-I-OUTPUT, command execution on node DBB1

    Virtual I/O Cache: Total Free In Use
    Cache Memory (MBytes) 250.00 157.10 92.89

    Granularity Hint Regions (pages): Total Free In Use
    Released
    %SYSMAN-I-OUTPUT, command execution on node APP1

    Virtual I/O Cache: Total Free In Use
    Cache Memory (MBytes) 250.00 24.14 225.85

    Granularity Hint Regions (pages): Total Free In Use
    Released
    %SYSMAN-I-OUTPUT, command execution on node APP2

    Virtual I/O Cache: Total Free In Use
    Cache Memory (MBytes) 375.00 0.00 375.00

    Granularity Hint Regions (pages): Total Free In Use
    Released
    SYSMAN>
    ------------------------------------------------------------------------
    ----------------------------------

    Sorry, the output looks kind of funky in proportional fonts...

    >
    > Cache and Oracle systems have their own memory structures and are not

    benefitted by XFC.
    > On AIX nodes we would reduce the file cache sizing as to not take

    memory away from Cache
    > memory structures.


    Again, this is VIOC, *not* XFC*. And I'm not particularly concerned
    about the database
    node. And 250 MB is not a big hit on a 40GB machine. :-)


    > What software is on the tier two?


    Its Cerner's Millennium. Thought I said that in the previous post...

    > Any Cache server page applications?


    Sorry, I don't understand the question.

    -Ken
    --
    Ken & Ann Fairfield
    What: Ken dot And dot Ann
    Where: Gmail dot Com


+ Reply to Thread