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IJ21542: DB2PREREQCHECK SHOULD NOT CHECK MODPROBE FILE WHEN USING MELLANOX CX-4 IB/ROCE CARD ON LINUX PLATFORM

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APAR status

  • Closed as fixed if next.

Error description

  • As of Mellanox ConnectX-4 IB and Roce HCA, there are no
    mlx4_core and mlx4_en module anymore, while , the Installation
    for V11.1 and V11.5 GA version still check whether options
    mlx4_core log_mtts_per_seg=7 in /etc/modprobe.d/modprobe.conf ,
    this is wrong , db2prereqcheck should not check this .
    
    For customer who use Mellanox ConnectX-4 HCA driver , may follow
    the topic "Preinstallation checklist for Db2 pureScale Feature
    (Linux) " in KC to configure the step 4   ,while cannot find the
    path <host-name>/sys/module/mlx4_core/parameters when go to
    check if it takes effect  , KC needs to rectify also defect
    should open to remove the pre-check of file modprobe
    
    https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.1.0/com
    .ibm.db2.luw.qb.server.doc/doc/r0057204.html
    Increase the Mellanox HCA driver mlx4_core parameter
    log_mtts_per_seg value from 3 (the default) to 7 on the host
    where the cluster caching facility (CF) resides. To increase the
    size, issue this command as root:
    
        Starting from SLES 12 and RHEL 6.10, these module options
    must be built into the initial image used by the kernel during
    boot:
    
        echo "options mlx4_core log_mtts_per_seg=7" >>
    /etc/modprobe.d/modprobe.conf
        dracut -f
        Copy
    
        On SLES 11:
    
        echo "options mlx4_core log_mtts_per_seg=7" >>
    /etc/modprobe.conf.local
        Copy
    
        On RHEL 6:
    
        echo "options mlx4_core log_mtts_per_seg=7" >>
    /etc/modprobe.d/modprobe.conf
        Copy
    
    For this change to take effect, you must reboot the server. To
    check whether your change is effective on the module, issue this
    command:
    
    <host-name>/sys/module/mlx4_core/parameters # cat
    /sys/module/mlx4_core/parameters/log_mtts_per_seg
    7
    

Local fix

  • We need to create this file /etc/modprobe.d/modprobe.conf for
    RHEL( or /etc/modprobe.conf.local for SLES)and put the entry in
    the file "options mlx4_core log_mtts_per_seg=7"  on each node to
    bypass installation
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Client that use ConnectX-4 on Linux                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * We need to create this file /etc/modprobe.d/modprobe.conf    *
    * for RHEL( /etc/modprobe.conf.local for SLES)and put the      *
    * entry in the file "options mlx4_core log_mtts_per_seg=7"  on *
    * each node to bypass installation.                            *
    ****************************************************************
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    IJ21542

  • Reported component name

    DB2 PURESCALE F

  • Reported component ID

    5724Y6900

  • Reported release

    B10

  • Status

    CLOSED FIN

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-12-11

  • Closed date

    2021-02-22

  • Last modified date

    2021-02-22

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels

[{"Line of Business":{"code":"LOB10","label":"Data and AI"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1"}]

Document Information

Modified date:
27 February 2021