I wonder what are the optimal Linux kernel parameters for oracle 11g db on 64-bit system.

I didn't find any detailed, good or full recommendations or best practices for this issue. Just found one recommendation that on 64-bit system it's good to set shmax half of the RAM.

  • 2
    Have you read the Linux Installation guide in the Oracle documentation? There's a section on Kernel Parameters. Find it here.
    – APC
    Commented Dec 1, 2014 at 7:01
  • 1
    @APC Yes i have read this. Also there is an important note in there "The kernel parameter and shell limit values shown in the following section are minimum values only. For production database systems, Oracle recommends that you tune these values to optimize the performance of the system." I need recommendations or best practices not the minimum values.
    – arminrock
    Commented Dec 1, 2014 at 7:10

3 Answers 3


The installation guide contains minimum (or recommended) values for each kernel parameter. On Metalink you can find at least one article (including formula) per each kernel parameter.

  • okay thank you. i will read the documentation more carefully.
    – arminrock
    Commented Dec 1, 2014 at 15:56

You need to refer Oracle installation guide but you should need to consider your server technical details too. If your server is having 64 GB physical memory then you can keep 1/3 SHMMAX size of this physical memory but it depends on server configuration and your requirements.

After setting SHMMAX, your SGA size cannot extend more than this SHMMAX size. If you want to extend SHMMAX size then you should need to bounce whole server which is not accepted in 24/7 environment. Due to this reason, be proper for setting up this kernel parameter. If you are running more than 1 instances/databases in same server then you need to take precaution for setting SHMMAX size


If you need best practices, not minimum required values, this is how to proceed : plan a meeting between the OS main administrator and the DB main administrator, and bring along the list of minumum requirements. If those people can't figure out "best practices", nobody can.

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