我使用 mdadm 从 4x4TB 驱动器设置了 Raid 5 阵列。但写入/读取速度非常慢，我想找出原因。它不受 CPU 限制，因为 I/O 操作期间的 CPU 使用率仅为 10% 左右。我还有 16GB 的 RAM，所以这可能也不是问题。
当我在我的 Windows 机器上测试时，普通驱动器的原始读/写速度在本地约为 130MB/s。
但是当使用dd从/dev/zero阵列写入时，速度仅为60MB/s 左右。
输出fdisk -l
Disk /dev/sdc: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: ST4000VN008-2DR1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/sdb: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: ST4000VN008-2DR1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/sde: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: ASM1156-PM
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: BD79C155-5BBE-11EB-8D66-D83BBFD957A0
Device Start End Sectors Size Type
/dev/sde1 2048 264191 262144 128M Microsoft reserved
/dev/sde2 264192 7814035455 7813771264 3.7T Microsoft Storage Spaces
Disk /dev/sdd: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: ASM1156-PM
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: BD79C15A-5BBE-11EB-8D66-D83BBFD957A0
Device Start End Sectors Size Type
/dev/sdd1 2048 264191 262144 128M Microsoft reserved
/dev/sdd2 264192 7814035455 7813771264 3.7T Microsoft Storage Spaces
输出mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sat Jun 12 15:06:35 2021
Raid Level : raid5
Array Size : 11720658432 (11177.69 GiB 12001.95 GB)
Used Dev Size : 3906886144 (3725.90 GiB 4000.65 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Sun Feb 6 17:41:49 2022
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Consistency Policy : bitmap
Name : filip-nas:0 (local to host filip-nas)
UUID : 5fe2775a:a8877735:a7bb8365:2f102649
Events : 16331
Number Major Minor RaidDevice State
0 8 48 0 active sync /dev/sdd
1 8 64 1 active sync /dev/sde
2 8 16 2 active sync /dev/sdb
4 8 32 3 active sync /dev/sdc
有什么想法可以解决这个问题吗？