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  • 15. Re: Allocation of memory to Oracle 11g instance
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    972145 wrote:
    Thanks for your answer but when I did,

    df -h

    on the server, it has not shown /dev/shm.
    Full version of guest o/s?

    Was it installed (from what media/distro)? Or is it a VM appliance that was downloaded?

    Oracle does not have to use +/dev/shm+ - such as when it is not configured for automatic memory management and using huge pages. This is however not the default configuration. For either RHEL-based systems or Oracle servers.

    So you need to provide more details - as sb92075 already requested.
  • 16. Re: Allocation of memory to Oracle 11g instance
    Aman.... Oracle ACE
    Currently Being Moderated
    972145 wrote:
    Thanks for your answer but when I did,

    df -h

    on the server, it has not shown /dev/shm.
    Can you show us that it's really not there?
    [oracle@edmtr2p0-orcl SPA]$ df -h
    Filesystem            Size  Used Avail Use% Mounted on
    /dev/sda5             194G   19G  165G  11% /
    /dev/sda2              23M  6.7M   15M  31% /boot
    tmpfs                 1.2G  232M  921M  21% /dev/shm
    /dev/sda1              30G   17G   13G  57% /mnt/cdrive
    [oracle@edmtr2p0-orcl SPA]$ 
    Aman....
  • 17. Re: Allocation of memory to Oracle 11g instance
    jgarry Guru
    Currently Being Moderated
    D'Oh! You're right, of course.
  • 18. Re: Allocation of memory to Oracle 11g instance
    975148 Newbie
    Currently Being Moderated
    Please find the output:-

    Filesystem Size Used Avail Use% Mounted on
    /dev/sda2 20G 1023M 18G 6% /
    /dev/mapper/VolGroup00-LogVol03
    15G 3.7G 11G 27% /var
    /dev/mapper/VolGroup00-LogVol02
    15G 166M 14G 2% /tmp
    /dev/mapper/VolGroup00-LogVol04
    11G 2.2G 7.9G 22% /usr
    /dev/mapper/VolGroup00-LogVol00
    4.9G 151M 4.5G 4% /home
    /dev/sda1 145M 13M 125M 10% /boot
    tmpfs 7.9G 4.1G 3.8G 53% /dev/shm
    /dev/mapper/oradatavg-oradatalv
    1008G 17G 941G 2% /d01
    /dev/mapper/orahomevg-u01lv
    40G 14G 24G 37% /u01
    /dev/mapper/orahomevg-oraarchlv
    109G 12G 92G 11% /oraarch
    /dev/mapper/orabackupvg-orabackuplv
    493G 199G 269G 43% /orabackup

    Here, 7.9G is allocated to /dev/shm but the SGA_MAX_SIZE parameter is set to 6448M.

    As per the information posted above, does it mean that 8 GB is allocated for Oracle as SGA_MAZSIZE is set to only 6448M?

    Regards
  • 19. Re: Allocation of memory to Oracle 11g instance
    975148 Newbie
    Currently Being Moderated
    The OS version is Red Hat Enterprise Linux Server release 5.8 Beta (Tikanga). The Oracle database is hosted on the OS which runs on vMware in a virtualised environment.
  • 20. Re: Allocation of memory to Oracle 11g instance
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    You need to determine how much RAM needs to be set aside as shared memory, to be used via the +/dev/shm+ interface.

    Let's say 16GB of RAM. You want 8GB for Oracle's SGA. You want between 256-512MB for ASM. And around another 512MB for running other s/w components that also need shm memory.

    So you decide 9GB of the 16GB needs to be shm memory.

    To implement:

    1) edit +/etc/fstab+ and update the +/dev/shm+ entry and add the parameter "size=9GB". Example:
    tmpfs      /dev/shm       tmpfs   defaults,size=9G 0 0
    2) to make this change immediate, without having to reboot, remount +/dev/shm+:
    mount -a /dev/shm
    Next, change the SGA parameter of Oracle to 8GB, shutdown the Oracle instance, and then start it. Confirm that it is now using a 8GB SGA.

    If this does not work for you, provide a copy-and-paste of the command(s) entered and the error response.
  • 21. Re: Allocation of memory to Oracle 11g instance
    975148 Newbie
    Currently Being Moderated

    I had a query that is the memory for user sessions depending on the max limit for user sessions as per sessions parameter would be extra as per your post? Can it be known how can the memory be calculated say if the max sessions is 300 and the current sessions are 100? I mean, the memory taken by the 100 user sessions.

  • 22. Re: Allocation of memory to Oracle 11g instance
    sb92075 Guru
    Currently Being Moderated

    975148 wrote:

     

    I had a query that is the memory for user sessions depending on the max limit for user sessions as per sessions parameter would be extra as per your post? Can it be known how can the memory be calculated say if the max sessions is 300 and the current sessions are 100? I mean, the memory taken by the 100 user sessions.

    HUH?

     

    How will you, I or anyone recognize a correct answer has been posted?

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