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Linux基础——IOPS计算方法及IO性能测试

news 2026/3/26 22:01:48

一、fio压测脚本及结果

[root@sysmt ~]# fio --name=writetest \
>     --filename=/root/testfile \
>     --size=1G \
>     --bs=4k \
>     --rw=write \
>     --direct=1
writetest: (g=0): rw=write, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=psync, iodepth=1
fio-3.7
Starting 1 process
writetest: Laying out IO file (1 file / 1024MiB)
Jobs: 1 (f=1): [W(1)][100.0%][r=0KiB/s,w=7495KiB/s][r=0,w=1873 IOPS][eta 00m:00s]
writetest: (groupid=0, jobs=1): err= 0: pid=3198: Wed Feb 11 15:17:24 2026write: IOPS=1814, BW=7259KiB/s (7434kB/s)(1024MiB/144445msec)clat (usec): min=212, max=10428, avg=546.43, stdev=341.82lat (usec): min=212, max=10429, avg=547.11, stdev=342.11clat percentiles (usec):|  1.00th=[  243],  5.00th=[  262], 10.00th=[  277], 20.00th=[  302],| 30.00th=[  334], 40.00th=[  383], 50.00th=[  445], 60.00th=[  515],| 70.00th=[  594], 80.00th=[  701], 90.00th=[  947], 95.00th=[ 1270],| 99.00th=[ 1827], 99.50th=[ 2024], 99.90th=[ 2540], 99.95th=[ 2802],| 99.99th=[ 4424]bw (  KiB/s): min= 4256, max= 8472, per=99.91%, avg=7252.52, stdev=766.31, samples=288iops        : min= 1064, max= 2118, avg=1813.00, stdev=191.62, samples=288lat (usec)   : 250=2.20%, 500=55.81%, 750=25.10%, 1000=8.03%lat (msec)   : 2=8.31%, 4=0.54%, 10=0.01%, 20=0.01%cpu          : usr=5.23%, sys=37.06%, ctx=257949, majf=0, minf=11IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%issued rwts: total=0,262144,0,0 short=0,0,0,0 dropped=0,0,0,0latency   : target=0, window=0, percentile=100.00%, depth=1Run status group 0 (all jobs):WRITE: bw=7259KiB/s (7434kB/s), 7259KiB/s-7259KiB/s (7434kB/s-7434kB/s), io=1024MiB (1074MB), run=144445-144445msecDisk stats (read/write):dm-0: ios=0/262078, merge=0/0, ticks=0/109905, in_queue=109905, util=100.00%, aggrios=0/262186, aggrmerge=0/10, aggrti                                                                                    cks=0/120727, aggrin_queue=18755, aggrutil=100.00%

二、IOPS计算方法

IOPS = Input/Output Operations Per Second
= 每秒输入/输出操作次数

吞吐量 (Throughput) = IOPS × 块大小 (Block Size)

示例：
- 如果 IOPS = 1000，块大小 = 4KB
- 吞吐量 = 1000 × 4KB = 4000 KB/s = 4 MB/s

测试结果：write: IOPS=1814, BW=7259KiB/s (7434kB/s)(1024MiB/144445msec)

bw=7259KB/s
bs（单块大小）=4KB
bw/bs=7259/4 ≈ 1814 IOPS

三、IO关键影响因素

┌─────────────────────────────────────────┐
│           IOPS 决定因素                  │
├─────────────────────────────────────────┤
│  1. 存储介质类型                         │
│     - SSD (SATA): 5,000-50,000 IOPS     │
│     - SSD (NVMe): 100,000-500,000 IOPS  │
│     - HDD: 50-200 IOPS                  │
├─────────────────────────────────────────┤
│  2. 访问模式                             │
│     - 顺序 (Sequential): 高吞吐量，低 IOPS │
│     - 随机 (Random): 低吞吐量，高 IOPS需求  │
├─────────────────────────────────────────┤
│  3. 块大小 (Block Size)                  │
│     - 小块 (4K): 考验 IOPS 能力           │
│     - 大块 (1M): 考验吞吐量能力            │
├─────────────────────────────────────────┤
│  4. I/O 队列深度 (Queue Depth)            │
│     - qd=1:  同步，低 IOPS                │
│     - qd=32: 并发，高 IOPS                │
├─────────────────────────────────────────┤
│  5. 读写比例                              │
│     - 纯读 / 纯写 / 混合读写               │
└─────────────────────────────────────────┘

四、如何测试真实IO能力

1、测试脚本：提高队列深度
[root@sysmt fio_test]# cat fio.sh
#!/bin/bash
# test_libaio_scaling.sh - libaio 引擎队列深度扩展测试for qd in 1 4 8 16 32 64 128 256; doecho ""echo "=========================================="echo "Queue Depth: $qd (libaio)"echo "=========================================="fio --name=libaio_qd${qd} \--filename=/root/fio_test/testfile \--size=1G \--bs=4k \--rw=randwrite \--direct=1 \--ioengine=libaio \--iodepth=${qd} \--runtime=30 \--time_based \--group_reporting \--output=/root/fio_test/fio_libaio_qd${qd}.log# 提取关键指标echo "--- 关键指标 ---"grep "IOPS=" /root/fio_test/fio_libaio_qd${qd}.log | tail -1grep "clat (usec): min=" /root/fio_test/fio_libaio_qd${qd}.log | tail -1grep "util=" /root/fio_test/fio_libaio_qd${qd}.log | tail -1rm -f /root/fio_test/testfilesleep 3
doneecho ""
echo "=========================================="
echo "汇总结果"
echo "=========================================="
for qd in 1 4 8 16 32 64 128 256; doecho -n "QD=$qd: "grep "IOPS=" /root/fio_test/fio_libaio_qd${qd}.log | tail -1 | awk -F'[=,]' '{print "IOPS=" $2}'
done

脚本中“\”后不能有空格，会触发类似报错：
fio: unable to open ' ' job file

2、测试结果：

[root@sysmt fio_test]# sh fio.sh

==========================================
Queue Depth: 1 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=3963KiB/s][r=0,w=990 IOPS][eta 00m:00s]
write: IOPS=877, BW=3509KiB/s (3593kB/s)(103MiB/30001msec)
clat (usec): min=19, max=11543, avg=911.80, stdev=595.33
sda: ios=0/26358, merge=0/5, ticks=0/25095, in_queue=13288, util=99.66%

==========================================
Queue Depth: 4 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=14.0MiB/s][r=0,w=3827 IOPS][eta 00m:00s]
write: IOPS=2606, BW=10.2MiB/s (10.7MB/s)(305MiB/30001msec)
clat (usec): min=193, max=85405, avg=1283.97, stdev=1006.26
sda: ios=0/78342, merge=0/21, ticks=0/71219, in_queue=32876, util=96.46%

==========================================
Queue Depth: 8 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=17.0MiB/s][r=0,w=4354 IOPS][eta 00m:00s]
write: IOPS=3841, BW=15.0MiB/s (15.7MB/s)(450MiB/30001msec)
clat (usec): min=240, max=52137, avg=1848.26, stdev=1077.67
sda: ios=0/115384, merge=0/8, ticks=0/104517, in_queue=47490, util=93.63%

==========================================
Queue Depth: 16 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=12.0MiB/s][r=0,w=3324 IOPS][eta 00m:00s]
write: IOPS=3735, BW=14.6MiB/s (15.3MB/s)(438MiB/30001msec)
clat (usec): min=230, max=61721, avg=4024.57, stdev=2091.76
sda: ios=0/116971, merge=0/1178, ticks=0/145392, in_queue=87932, util=89.58%

==========================================
Queue Depth: 32 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=12.5MiB/s][r=0,w=3193 IOPS][eta 00m:00s]
write: IOPS=3307, BW=12.9MiB/s (13.5MB/s)(388MiB/30001msec)
clat (usec): min=550, max=82181, avg=9377.25, stdev=4683.75
sda: ios=0/114356, merge=0/11157, ticks=0/166482, in_queue=108293, util=89.80%

==========================================
Queue Depth: 64 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=14.1MiB/s][r=0,w=3611 IOPS][eta 00m:00s]
write: IOPS=3863, BW=15.1MiB/s (15.8MB/s)(453MiB/30001msec)
clat (usec): min=323, max=67976, avg=16295.22, stdev=6576.48
sda: ios=0/136690, merge=0/16170, ticks=0/195029, in_queue=127382, util=91.11%

==========================================
Queue Depth: 128 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=15.3MiB/s][r=0,w=3921 IOPS][eta 00m:00s]
write: IOPS=3928, BW=15.3MiB/s (16.1MB/s)(460MiB/30002msec)
clat (usec): min=500, max=103954, avg=32291.48, stdev=10360.14
sda: ios=0/141620, merge=0/16742, ticks=0/255490, in_queue=185625, util=90.83%

==========================================
Queue Depth: 256 (libaio)
==========================================
--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=13.1MiB/s][r=0,w=3349 IOPS][eta 00m:00s]
write: IOPS=3769, BW=14.7MiB/s (15.4MB/s)(442MiB/30001msec)
clat (usec): min=332, max=221879, avg=67575.00, stdev=19432.98
sda: ios=0/137061, merge=0/16356, ticks=0/298153, in_queue=230416, util=90.39%

==========================================
汇总结果
==========================================
QD=1: IOPS=877
QD=4: IOPS=2606
QD=8: IOPS=3841
QD=16: IOPS=3735
QD=32: IOPS=3307
QD=64: IOPS=3863
QD=128: IOPS=3928
QD=256: IOPS=3769

3、分析测试结果

Queue Depth: 8 (libaio)处于最优队列

clat (usec): min=240, max=52137, avg=1848.26, stdev=1077.67

│ │ │ │ │ └─ 标准差（波动程度）

│ │ │ │ └─ 平均值（我说的 1.8ms）

│ │ │ └─ 最大时延（52ms，异常值）

│ │ └─ 最小时延（240μs，最佳情况）

│ └─ 单位：微秒（microsecond）

└─ completion latency：从提交到完成的总时延

常用IO时延指标clat：

| 指标 | 全称 | 含义 | 计算公式 |

| ------ | ------------------ | ---- | ----------- |

| `lat` | total latency | 总时延 | slat + clat |

关键指标：

IOPS=3841，BW=15.0MiB/s，avg=1848.26μs，util=93.63%

fio报告值：

QD=8: avg=1848.26 μs = 1.848 ms ≈ 1.8ms ✓

QD=16: avg=4024.57 μs = 4.025 ms ≈ 4.0ms ✓

用 Little's Law 验证（计算队列深度）：

Little's Law: 系统中平均请求数 = 到达率 × 平均时延

N = λ × W

在稳态下：

- 平均在途请求数 ≈ 实际队列深度（effective QD）

- 到达率 = IOPS

- 平均时延 = ?

反推验证：

QD=8: 实际并发度 = IOPS × 时延 = 3841 × 0.001848 ≈ 7.1 ≈ QD ✓

QD=16: 实际并发度 = 3735 × 0.004025 ≈ 15.0 ≈ QD ✓

队列深度16比队列深度8开销大2.18倍，存在明显劣势；

时延开销增长率：16队列时延翻倍

| QD | 平均时延 (μs) | 换算 (ms) | 相对 QD=8 |

| -- | --------- | ----------- | --------- |

| 8 | 1,848 | **1.85 ms** | 1.0× (基准) |

| 16 | 4,025 | **4.03 ms** | **2.18×** |

| 32 | 9,377 | **9.38 ms** | **5.07×** |

QD=8 → QD=16: (4025 - 1848) / 1848 = 2177 / 1848 = 117.8% 增长 ≈ 翻倍

正向并发队列对比（QD=8 → QD=16）：

- QD=8: 时延 1.8ms, IOPS 3,841

- QD=16: 时延应该保持 ~1.8ms, IOPS 应该达到 ~7,600

实际结果：

- QD=16: 时延 4.0ms（+118%）, IOPS 3,735（-3%）

这说明：

┌─────────────────────────────────────────┐

│ 系统无法并行处理 16 个请求 │

│ 请求在队列中排队等待，导致时延飙升 │

│ 实际并发度被限制在 ~8 左右 │

└─────────────────────────────────────────┘

[root@sysmt fio_test]# sh fio.sh
==========================================Queue Depth: 1 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=3963KiB/s][r=0,w=990 IOPS][eta 00m:00s] write: IOPS=877, BW=3509KiB/s (3593kB/s)(103MiB/30001msec) clat (usec): min=19, max=11543, avg=911.80, stdev=595.33 sda: ios=0/26358, merge=0/5, ticks=0/25095, in_queue=13288, util=99.66%
==========================================Queue Depth: 4 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=14.0MiB/s][r=0,w=3827 IOPS][eta 00m:00s] write: IOPS=2606, BW=10.2MiB/s (10.7MB/s)(305MiB/30001msec) clat (usec): min=193, max=85405, avg=1283.97, stdev=1006.26 sda: ios=0/78342, merge=0/21, ticks=0/71219, in_queue=32876, util=96.46%
==========================================Queue Depth: 8 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=17.0MiB/s][r=0,w=4354 IOPS][eta 00m:00s] write: IOPS=3841, BW=15.0MiB/s (15.7MB/s)(450MiB/30001msec) clat (usec): min=240, max=52137, avg=1848.26, stdev=1077.67 sda: ios=0/115384, merge=0/8, ticks=0/104517, in_queue=47490, util=93.63%
==========================================Queue Depth: 16 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=12.0MiB/s][r=0,w=3324 IOPS][eta 00m:00s] write: IOPS=3735, BW=14.6MiB/s (15.3MB/s)(438MiB/30001msec) clat (usec): min=230, max=61721, avg=4024.57, stdev=2091.76 sda: ios=0/116971, merge=0/1178, ticks=0/145392, in_queue=87932, util=89.58%
==========================================Queue Depth: 32 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=12.5MiB/s][r=0,w=3193 IOPS][eta 00m:00s] write: IOPS=3307, BW=12.9MiB/s (13.5MB/s)(388MiB/30001msec) clat (usec): min=550, max=82181, avg=9377.25, stdev=4683.75 sda: ios=0/114356, merge=0/11157, ticks=0/166482, in_queue=108293, util=89.80%
==========================================Queue Depth: 64 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=14.1MiB/s][r=0,w=3611 IOPS][eta 00m:00s] write: IOPS=3863, BW=15.1MiB/s (15.8MB/s)(453MiB/30001msec) clat (usec): min=323, max=67976, avg=16295.22, stdev=6576.48 sda: ios=0/136690, merge=0/16170, ticks=0/195029, in_queue=127382, util=91.11%
==========================================Queue Depth: 128 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=15.3MiB/s][r=0,w=3921 IOPS][eta 00m:00s] write: IOPS=3928, BW=15.3MiB/s (16.1MB/s)(460MiB/30002msec) clat (usec): min=500, max=103954, avg=32291.48, stdev=10360.14 sda: ios=0/141620, merge=0/16742, ticks=0/255490, in_queue=185625, util=90.83%
==========================================Queue Depth: 256 (libaio)==========================================--- 关键指标 ---w(1)][100.0%][r=0KiB/s,w=13.1MiB/s][r=0,w=3349 IOPS][eta 00m:00s] write: IOPS=3769, BW=14.7MiB/s (15.4MB/s)(442MiB/30001msec) clat (usec): min=332, max=221879, avg=67575.00, stdev=19432.98 sda: ios=0/137061, merge=0/16356, ticks=0/298153, in_queue=230416, util=90.39%
==========================================汇总结果==========================================QD=1: IOPS=877QD=4: IOPS=2606QD=8: IOPS=3841QD=16: IOPS=3735QD=32: IOPS=3307QD=64: IOPS=3863QD=128: IOPS=3928QD=256: IOPS=3769

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