kernel parms
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Thread: kernel parms

  1. #1
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    I have seen some documents on kernel parms from oracle which i have found. I am trying to understand which underlaying kernel parms are used for oracle. I know the following parms are discussed by oracle but havent seen docs talk about maxdsiz or maxdsiz64 parms. What i am looking for is a doc that talks about oracle errors and its related kernel parm.

    SHMMAX Maximum size of shared memory segment (bytes) 250kB + 8.2kB * shared_buffers + 14.2kB * max_connections or infinity
    SHMMIN Minimum size of shared memory segment (bytes) 1
    SHMALL Total amount of shared memory available (bytes or pages) if bytes, same as SHMMAX; if pages, ceil(SHMMAX/PAGE_SIZE)
    SHMSEG Maximum number of shared memory segments per process only 1 segment is needed, but the default is much higher
    SHMMNI Maximum number of shared memory segments system-wide like SHMSEG plus room for other applications
    SEMMNI Maximum number of semaphore identifiers (i.e., sets) >= ceil(max_connections / 16)
    SEMMNS Maximum number of semaphores system-wide ceil(max_connections / 16) * 17 + room for other applications
    SEMMSL Maximum number of semaphores per set >= 17
    SEMMAP Number of entries in semaphore map see text
    SEMVMX Maximum value of semaphore
    "High Salaries = Happiness = Project Success."

  2. #2
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    Immediate answer I can give for
    SEMMSL value......
    if it is less than your processes values set in init.ora file..
    we will find the interesting results.....meaning
    1.allocation of more than one semaphore per database...(ipcs command)
    2.If you have multy instances in same server...other instances
    will not startup giving error...
    ORA-27300: OS system dependent operation:semctl failed with status: 22
    ORA-27301: OS failure message: Invalid argument
    ORA-27302: failure occurred at: sskgpwrm1..

    so the value should be always processes value+4..
    Thanks.
    Thanigaivasan.


  3. #3
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    thanks for your response. Can you or somebody explain me how to use the ipcs command? and how to read the outout and interpret?
    "High Salaries = Happiness = Project Success."

  4. #4
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    simple.....
    I hope you are working in UNIX....
    eg....adn columns are self explainatory....
    SERVER% ipcs
    IPC status from as of Thu Jun 6 10:21:15 2002
    T ID KEY MODE OWNER GROUP
    Message Queues:
    Shared Memory:
    m 24000 0x0f1fa0d4 --rw-r----- oracle dba
    m 30001 0x929ec53c --rw-r----- oracle dba
    m 2 00000000 --rw-rw-rw- root root
    m 22003 0x8dd0048c --rw-r----- oracle dba
    m 20004 0xc07875b8 --rw-r----- oracle dba
    m 24005 0xc8e246ec --rw-r----- oracle dba
    m 24006 0x88b6e5b8 --rw-r----- oracle dba
    m 7 0xc7ae96c0 --rw-r----- oracle dba
    Semaphores:
    s 0 0x000187cf --ra-ra-ra- root root
    s 786433 00000000 --ra-r----- oracle dba
    s 4915202 0x1c3f102c --ra-r----- oracle dba
    s 3 00000000 --ra-ra-ra- root root
    s 3342340 0x4507b348 --ra-r----- oracle dba
    s 2818053 0x3e8c9be0 --ra-r----- oracle dba
    s 3342342 0xb9518478 --ra-r----- oracle dba
    s 2293767 0x4467b348 --ra-r----- oracle dba
    s 196616 0x3c3f102c --ra-r----- oracle dba
    ...see I have 7 databases...in this server...it gives the sehared memory amd semaphore allocatuons...to those DB..

    ipcs-a......gives all...including the semaphore allocations /set in a database.
    Thanks.
    Thanigaivasan.



  5. #5
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    Thanigaivasan, thank you for that info. What i was also looking for is how to add up the memory given to oracle. There is a limit of i think 1.75 gig of memory given to oracle no matter how many isntances you have. I think if you want to have more instances which demands more memory allocated to oracle then you have to create "memory windows". Do you know anything about that?

    -Jigar
    "High Salaries = Happiness = Project Success."

  6. #6
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    SGA.....value for the instances...
    Thanks.
    Thanigaivasan.

  7. #7
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    Originally posted by jlakhani
    There is a limit of i think 1.75 gig of memory given to oracle no matter how many isntances you have
    no such limit, we have 2 instances running on suse with 1.2GB sga each so that 2.4GB and no problems at all

  8. #8
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    Pando thanks for your response. If there is no limit then when would you use memory windows?
    "High Salaries = Happiness = Project Success."

  9. #9
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    I have never heard of memory windows

    solaris? tru64?

  10. #10
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    The limit of 1.75G RAM is for 32bit Oracle running on HP-UX 10/11 (32/64 bit). To overcome this you have to use the memory windows technology or else upgrade to 64bit oracle on 64bit HP-UX (versions 11.00 and above I believe).

    -amar

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