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shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

  • 1.  shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 04:04 PM

    Hey gurus,

    What do I need to increase to allow the database the ability to add additional virtual memory segments?  HCL person could not answer my question when I opened the case and I have dozens of servers getting the same message.

     

    -- 

    Thanks,

    Kate Tomchik She/Her/Hers

    Principal Systems Engineer, Database Solutions

    The Home Depot 

    Cell: 678-427-4914 (Text preferred)

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    INTERNAL USE


    #Informix


  • 2.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 04:11 PM
    Kate:

    Probably it will be the shmseg setting.

    Art

    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
    ------------------------------

    Original Message


  • 3.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 04:12 PM
    Oops, that got away from me. It could be shmseg or shmmni.

    Art

    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
    ------------------------------

    Original Message


  • 4.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 04:14 PM
    How depends on the OS, check the releases notes

    --
    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529

    Oninit is a Registered Trademark of Oninit LLC


    Original Message


  • 5.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 05:05 PM

    Redhat 6 and I have already confirmed we have all the Kernel paramaters set as the release notes say.

     

     

    -- 

    Thanks,

    Kate Tomchik She/Her/Hers

    Principal Systems Engineer, Database Solutions

    The Home Depot 

    Cell: 678-427-4914 (Text preferred)

    For non-urgent requests create a TICKET:

    https://servicecatalog.apps.homedepot.com/home/catalog/Databases/databasesupport

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    Original Message


  • 6.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 05:24 PM
    Kate:

    The release note settings for kernel parameters are minimums and are simply values that allowed the Informix techs to start and test the engine. You may certainly need higher settings for some. When you have many instances on a host, shmmninis one of those.

    Art

    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
    ------------------------------

    Original Message


  • 7.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 05:27 PM
    run the command

    $ sudo sysctl -a | grep shm
    kernel.shmmax = 68719476736
    kernel.shmall = 4294967296
    kernel.shmmni = 4096
    vm.hugetlb_shm_group = 0

    Where

    SHMMNI ??? This parameter sets the system wide maximum number of shared
    memory segments.
    SHMALL ??? This parameter sets the total amount of shared memory pages
    that can be used system wide. Hence, SHMALL should always be at least
    ceiling(shmmax/PAGE_SIZE).
    SHMMAX ??? This parameter defines the maximum size in bytes of a single
    shared memory segment that a Linux?? process can allocate in its virtual
    address space.

    --
    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529

    Oninit is a Registered Trademark of Oninit LLC


    Original Message


  • 8.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 04:18 PM
    Hi Kate,

    You are likely bumping into one of the kernel limits, like SHMMAX or something.

    I don't know what OS you are using, but try running lsipc and see if that shows that you are close to any of the limits.  iscs -l (that's an "L") will also show your shared memory limits.

    Do you have a lot of virtual memory segments that have been added dynamically (onstat -g seg)?  If so, then onmode -F may buy you some time.


    ------------------------------
    Mike Walker
    xDB Systems, Inc
    www.xdbsystems.com
    ------------------------------

    Original Message


  • 9.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 05:22 PM

    Share memory is running crazy

     

    /home/informix> onstat -g seg

     

    IBM Informix Dynamic Server Version 12.10.FC13 -- On-Line -- Up 3 days 06:55:28 -- 302260 Kbytes

     

    Segment Summary:

    id         key        addr             size             ovhd     class blkused  blkfree

    1015815    525f4801   44000000         13893632         601096   R     3392     0

    1048584    525f4802   44d40000         144678912        1697112  V     35152    170

    1081353    525f4803   4d73a000         11632640         1        B     2840     0

    1114122    525f4804   4e252000         21307392         1        B     5202     0

    1146891    525f4805   4f6a4000         561152           7848     M     136      1

    1179660    525f4806   4f72d000         16777216         198072   V     3641     455

    1212429    525f4807   5072d000         16777216         198072   V     3280     816

    1245198    525f4808   5172d000         16777216         198072   V     2912     1184

    1277967    525f4809   5272d000         16777216         198072   V     3512     584

    1310736    525f480a   5372d000         16777216         198072   V     1415     2681

    1343505    525f480b   5472d000         16777216         198072   V     2937     1159

    1376274    525f480c   5572d000         16777216         198072   V     174      3922

    Total:     -          -                309514240        -        -     64593    10972

     

       (* segment locked in memory)

    No reserve memory is allocated

     

    >lsipc

    No such file or directory

     

    >iscs -l

    No su file or directory

    -- 

    Thanks,

    Kate Tomchik She/Her/Hers

    Principal Systems Engineer, Database Solutions

    The Home Depot 

    Cell: 678-427-4914 (Text preferred)

    For non-urgent requests create a TICKET:

    https://servicecatalog.apps.homedepot.com/home/catalog/Databases/databasesupport

    Choose experience: IT-09034-Database Solutions Operations

     

     




    Original Message


  • 10.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Mon November 28, 2022 07:46 PM
    That doesn't seem too crazy, and the memory footprint is still quite small, but it may still be more than normal so may be hitting OS limits...especially if you have multiple instances on the server.  I still think that's the likely problem that you are hitting, but the underlying problem may be something consuming more memory than usual.

    Sorry, I mistyped one of those commands...should be ipcs -l (that's an "L")

    You may want to check the Informix log to see when the memory segments were added and whether that corresponds to the failure to allocate shared memory.  Also check to see if the lock table has been dynamically expanded as that can be responsible for adding more memory segments (onstat -k | tail).


    ------------------------------
    Mike Walker
    xDB Systems, Inc
    www.xdbsystems.com
    ------------------------------

    Original Message


  • 11.  RE: shmget: [ENOSPC][28]: key 525f4802: The server could not allocate shared memory because an operating system limit was reached

    Posted Wed November 30, 2022 09:06 AM
    Hi Kate, 
    A few weeks ago, our main engine became to get into the same problem here , IFX 12.15FC15 / RH 7.4.

    Here, at least three times the instance crashed with AF and memory dump because they aren't able to allocate more memory. 
    However, our configuration is set the same for years and never get any like this. 

    Yesterday, again we get into the same problem, luckily, the instance not crashed. 
     I was able to collect few information to the HCL support where I have my own suspicious the engine isn't freeing the virtual segments, where they have something pointing to it, but no session or memory pool is really using them... then they became to allocating more and more as the workload of the moment requires until they crash... and the "onmode -F" doesn't free them. 

    If I have any news about my case, if became detected some defect, I will share it here. 







    ------------------------------
    Cesar Martins
    ------------------------------

    Original Message