Shared Memory
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  1. #1
    Join Date
    Jan 2001
    Posts
    138
    We are having problems bringing up databases on our development box. When we try to bring up a couple, the following error comes up.

    ORA-07279: spcre: semget error, unable to get first semaphore set.
    SVR4 Error: 28: No space left on device
    Additional information: 1

    We have 7 databases. The total #processes are 1924. Shared memory parameters are:

    set semsys:seminfo_semmni=256
    set semsys:seminfo_semmns=4096
    set semsys:seminfo_semmsl=256
    set shmsys:shminfo_shmmax=2147483648
    set shmsys:shminfo_shmmni=200
    set shmsys:shminfo_shmseg=20
    set shmsys:shminfo_shmmin=1

    This problem appeared suddenly. I wonder if there is/are some processes hogging shared memory. How do I find out what those are?

    I am thinking of doing one of these.

    1. Do ipcs -b. Then shut down all the databases. ipcs -b again and see anything is still there. If yes, kill it with ipcsrm -m .

    2. Reboot the machine.

    Any ideas are appreciated. Thanks.

  2. #2
    Check the /swap space, it might be too small.
    Or sum all the SGA size of the 7 databases, make sure you have enough memory.
    Queyon Zeng

  3. #3
    Join Date
    Jan 2001
    Posts
    126
    Hi,

    The semaphore settings seem to be OK. Important ones are

    SEMMSL = 10+Largest # of processes in any database
    SEMMNS = Sum of all procs in all DB (add largest twice) + 10

    You can increase SHMMAX. I don't know what is the total RAM on your system.

    If you plan to reboot don't bother to kill the process holding the memory segment. Reboot will take care of it. Shutdown all DBs and reboot the system and then try.

    Baliga

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