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  • Round robin on a blade JS20

    From sbzx@21:1/5 to Michel B on Sun Mar 11 03:27:58 2018
    I understand that it's a bit late now but here's the solution.

    It seems that algorithm=round_robin requires reserve_policy=no_reserve. So try "chdev -l <disk> -a algorithm=round_robin -a reserve_policy=no_reserve -P", perhaps even add "-a queue_depth=<a value higher than 1>".

    Regards,
    sbzx

    On Wednesday, 30 November 2005 02:47:10 UTC, Michel B wrote:
    I want to change the algorithm for a blade JS20 from default
    "fail_over" into "round_robin".
    But when I try to change this, I get the following error message.

    chdev -l hdisk1 -a algorithm=round_robin
    Method error (/usr/lib/methods/chgdisk):
    0514-018 The values specified for the following attributes
    are not valid:
    (no message after this last line. Disk is not in use, VG is exported)


    The following command tells me it is possible though...
    # lsattr -El hdisk1 -R -a algorithm
    fail_over
    round_robin


    System info:
    - AIX 5.2 RML07, using MPIO
    - two fibre adapters
    - no internal disks, all disks defined on a Shark
    - # lsattr -El hdisk1
    PCM PCM/friend/fcpother Path Control Module
    False
    algorithm fail_over Algorithm
    True
    clr_q no Device CLEARS its
    Queue on error True
    dist_err_pcnt 0 Distributed Error
    Percentage True
    dist_tw_width 50 Distributed Error
    Sample Time True
    hcheck_cmd test_unit_rdy Health Check Command
    True
    hcheck_interval 0 Health Check Interval
    True
    hcheck_mode nonactive Health Check Mode
    True
    location Location Label
    True
    lun_id 0x5002000000000000 Logical Unit Number ID
    False
    max_transfer 0x40000 Maximum TRANSFER Size
    True
    node_name 0x5005076300c09d75 FC Node Name
    False
    pvid 000000008ea526ed0000000000000000 Physical volume
    identifier False
    q_err yes Use QERR bit
    True
    q_type simple Queuing TYPE
    True
    queue_depth 1 Queue DEPTH
    True
    reassign_to 120 REASSIGN time out
    value True
    reserve_policy single_path Reserve Policy
    True
    rw_timeout 30 READ/WRITE time out
    value True
    scsi_id 0x611400 SCSI ID
    False
    start_timeout 60 START unit time out
    value True
    ww_name 0x5005076300c89d75 FC World Wide Name
    False


    I want to change it because I need the throughput.
    Anybody any thoughts about this?

    Thanks,
    Michel

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