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7.2. 存储集群

Ceph 包含 rados bench 命令,用于对 RADOS 存储集群执行性能基准测试。命令将执行写入测试和两种类型的读取测试。在测试读写性能时使用 --no-cleanup 选项。默认情况下,rados bench 命令将删除它写入存储池中的对象。离开这些对象后,有两个读取测试可以测量顺序和随机读取性能。

注意

在运行这些性能测试前,运行以下命令丢弃所有文件系统缓存:

# echo 3 | sudo tee /proc/sys/vm/drop_caches && sudo sync
  1. 创建新存储池:

    # ceph osd pool create testbench 100 100
  2. 对新创建的存储池执行 10 秒写入测试:

    # rados bench -p testbench 10 write --no-cleanup

    输出示例

    Maintaining 16 concurrent writes of 4194304 bytes for up to 10 seconds or 0 objects
     Object prefix: benchmark_data_cephn1.home.network_10510
       sec Cur ops   started  finished  avg MB/s  cur MB/s  last lat   avg lat
         0       0         0         0         0         0         -         0
         1      16        16         0         0         0         -         0
         2      16        16         0         0         0         -         0
         3      16        16         0         0         0         -         0
         4      16        17         1  0.998879         1   3.19824   3.19824
         5      16        18         2   1.59849         4   4.56163   3.87993
         6      16        18         2   1.33222         0         -   3.87993
         7      16        19         3   1.71239         2   6.90712     4.889
         8      16        25         9   4.49551        24   7.75362   6.71216
         9      16        25         9   3.99636         0         -   6.71216
        10      16        27        11   4.39632         4   9.65085   7.18999
        11      16        27        11   3.99685         0         -   7.18999
        12      16        27        11   3.66397         0         -   7.18999
        13      16        28        12   3.68975   1.33333   12.8124   7.65853
        14      16        28        12   3.42617         0         -   7.65853
        15      16        28        12   3.19785         0         -   7.65853
        16      11        28        17   4.24726   6.66667   12.5302   9.27548
        17      11        28        17   3.99751         0         -   9.27548
        18      11        28        17   3.77546         0         -   9.27548
        19      11        28        17   3.57683         0         -   9.27548
     Total time run:         19.505620
    Total writes made:      28
    Write size:             4194304
    Bandwidth (MB/sec):     5.742
    
    Stddev Bandwidth:       5.4617
    Max bandwidth (MB/sec): 24
    Min bandwidth (MB/sec): 0
    Average Latency:        10.4064
    Stddev Latency:         3.80038
    Max latency:            19.503
    Min latency:            3.19824

  3. 对存储池执行 10 秒的后续读取测试:

    # rados bench -p testbench 10 seq

    输出示例

    sec Cur ops   started  finished  avg MB/s  cur MB/s  last lat   avg lat
      0       0         0         0         0         0         -         0
    Total time run:        0.804869
    Total reads made:      28
    Read size:             4194304
    Bandwidth (MB/sec):    139.153
    
    Average Latency:       0.420841
    Max latency:           0.706133
    Min latency:           0.0816332

  4. 对存储池执行 10 秒随机读取测试:

    # rados bench -p testbench 10 rand

    输出示例

    sec Cur ops   started  finished  avg MB/s  cur MB/s  last lat   avg lat
      0       0         0         0         0         0         -         0
      1      16        46        30   119.801       120  0.440184  0.388125
      2      16        81        65   129.408       140  0.577359  0.417461
      3      16       120       104   138.175       156  0.597435  0.409318
      4      15       157       142   141.485       152  0.683111  0.419964
      5      16       206       190   151.553       192  0.310578  0.408343
      6      16       253       237   157.608       188 0.0745175  0.387207
      7      16       287       271   154.412       136  0.792774   0.39043
      8      16       325       309   154.044       152  0.314254   0.39876
      9      16       362       346   153.245       148  0.355576  0.406032
     10      16       405       389   155.092       172   0.64734  0.398372
    Total time run:        10.302229
    Total reads made:      405
    Read size:             4194304
    Bandwidth (MB/sec):    157.248
    
    Average Latency:       0.405976
    Max latency:           1.00869
    Min latency:           0.0378431

  5. 要增加并发读写的数量,使用 -t 选项,默认是 16 个线程。另外,-b 参数可以调整要写入的对象的大小。默认对象大小为 4MB。安全的最大对象大小为 16MB。红帽建议在不同的池中运行这些基准测试的多个副本。这样做可显示多个客户端的性能变化。

    添加 --run-name <label> 选项来控制在基准测试过程中写入的对象的名称。通过更改每个正在运行的命令实例的 --run-name 标签,可以同时运行多个 rados bench 命令。这可以防止多个客户端尝试访问同一对象并允许不同的客户端访问不同的对象时可能会出现 I/O 错误。--run-name 选项在尝试模拟实际工作负载时也很有用。例如:

    # rados bench -p testbench 10 write -t 4 --run-name client1

    输出示例

    Maintaining 4 concurrent writes of 4194304 bytes for up to 10 seconds or 0 objects
     Object prefix: benchmark_data_node1_12631
       sec Cur ops   started  finished  avg MB/s  cur MB/s  last lat   avg lat
         0       0         0         0         0         0         -         0
         1       4         4         0         0         0         -         0
         2       4         6         2   3.99099         4   1.94755   1.93361
         3       4         8         4   5.32498         8     2.978   2.44034
         4       4         8         4   3.99504         0         -   2.44034
         5       4        10         6   4.79504         4   2.92419    2.4629
         6       3        10         7   4.64471         4   3.02498    2.5432
         7       4        12         8   4.55287         4   3.12204   2.61555
         8       4        14        10    4.9821         8   2.55901   2.68396
         9       4        16        12   5.31621         8   2.68769   2.68081
        10       4        17        13   5.18488         4   2.11937   2.63763
        11       4        17        13   4.71431         0         -   2.63763
        12       4        18        14   4.65486         2    2.4836   2.62662
        13       4        18        14   4.29757         0         -   2.62662
    Total time run:         13.123548
    Total writes made:      18
    Write size:             4194304
    Bandwidth (MB/sec):     5.486
    
    Stddev Bandwidth:       3.0991
    Max bandwidth (MB/sec): 8
    Min bandwidth (MB/sec): 0
    Average Latency:        2.91578
    Stddev Latency:         0.956993
    Max latency:            5.72685
    Min latency:            1.91967

  6. 删除 rados bench 命令创建的数据:

    # rados -p testbench cleanup