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IT30533:启用重复数据删除的VSNAP性能慢于预期

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您可以跟踪此组件的所有活动APAR。

 

APAR状态

  • 作为程序错误关闭。

错误描述

  • vSnap performance with deduplication enabled is slower than
    expected because the cache is not behaving as expected.
    
    This is due to a change in the default settings that control
    vSnap cache writes. Verify the following settings on the vSnap.
    [[email protected] ~]$ cat
    /sys/module/zfs/parameters/l2arc_write_max
    2147483648
    [[email protected] ~]$ cat
    /sys/module/zfs/parameters/l2arc_write_boost
    2147483648
    
    If the results match above settings, the vSnap is configured
    using 10.1.4 default settings and this APAR applies.
    These settings can result in excessive writes to the cache
    device, limiting the ability for the cache to provide the
    optimization's for deduplication, for which it is intended.
    
    IBM Spectrum Protect Plus Versions Affected:
    IBM Spectrum Protect Plus 10.1.4
    
    Initial Impact: Medium
    
    Additional Keywords: SPP, SPPlus, TS002794203
    

本地修复

  • The local fix consists of two steps.
    1. To change the settings that control cache writes immediately,
    run:
        sudo bash
        echo 8388608 > /sys/module/zfs/parameters/l2arc_write_max
        echo 8388608 > /sys/module/zfs/parameters/l2arc_write_boost
    A reboot is not required after making change above, but the
    change may be lost if the vSnap server is rebooted for any other
    reason.
    2. To make sure the change persists after the next reboot, run:
        sudo bash
        echo "options zfs l2arc_write_max=8388608" >>
    /etc/modprobe.d/zfs.conf
        echo "options zfs l2arc_write_boost=8388608" >>
    /etc/modprobe.d/zfs.conf
    

问题摘要

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * IBM Spectrum Protect Plus level 10.1.4.                      *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Apply fixing level when available. This problem is currently *
    * projected to be fixed in IBM Spectrum Protect Plus level     *
    * 10.1.5. Note that this is subject to change at the           *
    * discretion of IBM.                                           *
    ****************************************************************
    

问题结论

  • Starting with IBM Spectrum Protect Plus level 10.1.4, the
    default configuration on vSnap servers was tuned in a way that
    increased the rate at which data was written to the storage
    pool's cache device. This configuration was intended to improve
    the usage of the cache device. However, under certain conditions
    this tuning was found to increase the rate by an excessive
    amount which caused the storage pool to spend a
    disproportionately high amount of time writing to the cache
    device at the expense of overall write throughput when
    deduplication was enabled.
    
    The problem has been resolved by reducing the default rate at
    which data is written to cache devices. The new rate is now
    tuned in a way that uses a balanced approach that optimizes the
    use of the cache device as as well overall write throughput.
    

临时修复

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APAR信息

  • Apar号码

    IT30533

  • 报告的组件名称

    SP加

  • 报告的组件ID.

    5737Splus.

  • 报告释放

    A10

  • 状态

    关闭

  • PE.

    没有

  • 侯赛人

    no

  • 特别关注

    nospecatt / xsystem.

  • 提交日期

    2019-10-18

  • 关闭日期

    2019-11-13

  • 最后修改日期

    2019-11-13

  • APAR是由以下一个或多个中的SYSROUTED:

  • APAR被SISROUTED到以下一个或多个:

修复信息

  • 固定组件名称

    SP加

  • 固定组件ID

    5737Splus.

适用组件级别

[{"Line of Business":{"code":"LOB10","label":"Data and AI"},"Business Unit":{"code":"BU029","label":"Software"},"Product":{"code":"SSNQFQ","label":"IBM Spectrum Protect Plus"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.1.0"}]

文件信息

修改日期:
07 February 2021