Friday, August 7, 2009

ORA-27102: out of memory on Linux, unable to startup instance

Lower value of “kernel.shmall” in /etc/sysctl.conf will result “ORA—27102: out of memory” error on Linux x86_64, set the value using below Formula.

kernel.shmall = kernel.shmmax/PAGE_SIZE

Run the below command to get the value of PAGE_SIZE.
$getconf PAGE_SIZE

The kernel.shmmax parameter should be greater than or equal to the Half the size of physical memory (recommended value) of the machine. If the amount of Physical memory is ever changed then the parameter should be adjusted accordingly.

To make the new kernel settings take effect immediately, run this command:$/sbin/sysctl -p

Click here to see How to resolve ORA-27102 error on Solaris.
Satishbabu Gunukula


  1. Hello, I have the same error but in a SUSE Linux Enterprise Server 10 (i586) with 32 bits.

    The kernel parameters are:

    kernel.shmall = 268435200
    kernel.shmmax = 4294967295

    and the kernel version is:

    Linux db-r2-01 #1 SMP Thu May 17 14:00:09 UTC 2007 i686 i686 i386 GNU/Linux

    If this error appear RedHat it would be fix updating the kernel to hugemem version as explain the DOC ID 746178.1 of Metalink. But in Suse I haven´t idea.

    Any suggestion? Thanks.

  2. Hi,

    What are you doing, when you received ORA-27102 error?

    Did you see all my posts on this error? Did you try the workaround?

    See the posts under "Ora-Errors" category.

    Satishbabu Gunukula

  3. Hello Satishbabu Gunukula, thanks for your answer.

    The database(10g R2)have 1168M in sga_max_size, so I tried to increase it to 2000M because the server have 4GB of physical memory, and in the moment of startup appear this error.

    Yes, I read all your posts about this errors and I have checked all the kernel parameters. Now I change the shmall to shmmax/page_size, in spite of this change the database don´t start.

    If you need more information about the situation, please tell me.


  4. Hi,

    This error indicates that the SGA is large for the amount of shared memory you have allocated in kernel configuration file.

    See the below post and try workaround 1 and 2

    The same issue has been resolved for many clients with this workaround.

    Satishbabu Gunukula

  5. hi satish,

    Please send me how to migrate database from DB2 to Oracle 10.2g or 11g

  6. Hi Niranjan,

    Please see the below posts

    Satishbabu Gunukula