我使用了 2 个分区来创建 RAID1 阵列。
两者都是967131168个扇区，每个扇区512字节。
所以raid数组大小应该是483564544。
但它显示：
Array Size : 483433472 (461.04 GiB 495.04 GB)
Used Dev Size : 483433472 (461.04 GiB 495.04 GB)
当我增加数组大小时，它说：
root@GalensSynology:~# mdadm --grow /dev/md2 --size=max
mdadm: component size of /dev/md2 unchanged at 483433472K
我尝试强制设置数组大小，但出现错误：
root@GalensSynology:~# mdadm --grow /dev/md2 --size=483564544
mdadm: Cannot set device size for /dev/md2: No space left on device
RAID 阵列信息：
root@GalensSynology:~# mdadm --query --detail /dev/md2
/dev/md2:
Version : 1.2
Creation Time : Thu Sep 26 14:46:34 2019
Raid Level : raid1
Array Size : 483433472 (461.04 GiB 495.04 GB)
Used Dev Size : 483433472 (461.04 GiB 495.04 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Thu Aug 11 21:49:15 2022
State : active
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : GalensSynology:2 (local to host GalensSynology)
UUID : ce0e9aff:a0d43a65:acbf6b7f:d9786045
Events : 1217
Number Major Minor RaidDevice State
0 8 51 0 active sync /dev/sdd3
1 8 19 1 active sync /dev/sdb3
磁盘分区信息：
root@GalensSynology:~# fdisk -l /dev/sdb
Disk /dev/sdb: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xbc7bdaae
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 4982527 4980480 2.4G fd Linux raid autodetect
/dev/sdb2 4982528 9176831 4194304 2G fd Linux raid autodetect
/dev/sdb3 9437184 976568351 967131168 461.2G fd Linux raid autodetect
root@GalensSynology:~# fdisk -l /dev/sdd
Disk /dev/sdd: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x5f55e8f4
Device Boot Start End Sectors Size Id Type
/dev/sdd1 2048 4982527 4980480 2.4G fd Linux raid autodetect
/dev/sdd2 4982528 9176831 4194304 2G fd Linux raid autodetect
/dev/sdd3 9437184 976568351 967131168 461.2G fd Linux raid autodetect
但另一个 raid 阵列在同一设备上运行良好：
root@GalensSynology:~# mdadm --query --detail /dev/md5
/dev/md5:
Version : 1.2
Creation Time : Thu Aug 11 21:17:31 2022
Raid Level : raid1
Array Size : 483564544 (461.16 GiB 495.17 GB)
Used Dev Size : 483564544 (461.16 GiB 495.17 GB)
Raid Devices : 1
Total Devices : 1
Persistence : Superblock is persistent
Update Time : Thu Aug 11 21:20:33 2022
State : clean
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
Name : GalensSynology:5 (local to host GalensSynology)
UUID : 90e5ba00:0ac44575:d3356c1a:4949e120
Events : 1
Number Major Minor RaidDevice State
0 8 35 0 active sync /dev/sdc3
和磁盘信息：
root@GalensSynology:~# fdisk -l /dev/sdc
Disk /dev/sdc: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xd0050b12
Device Boot Start End Sectors Size Id Type
/dev/sdc1 2048 4982527 4980480 2.4G fd Linux raid autodetect
/dev/sdc2 4982528 9176831 4194304 2G fd Linux raid autodetect
/dev/sdc3 9437184 976568351 967131168 461.2G fd Linux raid autodetect
感谢霜舒兹。
是的，数据偏移量不同。
root@GalensSynology:/volume2/homes/galenzhao# mdadm --examine /dev/sdb3
/dev/sdb3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : ce0e9aff:a0d43a65:acbf6b7f:d9786045
Name : GalensSynology:2 (local to host GalensSynology)
Creation Time : Thu Sep 26 14:46:34 2019
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 966866976 (461.04 GiB 495.04 GB)
Array Size : 483433472 (461.04 GiB 495.04 GB)
Used Dev Size : 966866944 (461.04 GiB 495.04 GB)
Data Offset : 264192 sectors
Super Offset : 8 sectors
Unused Space : before=264112 sectors, after=32 sectors
State : clean
Device UUID : 4d219454:64cd59fa:8e469f08:992bdf59
Update Time : Thu Aug 11 22:58:13 2022
Bad Block Log : 512 entries available at offset 16 sectors
Checksum : 38317e71 - correct
Events : 1220
Device Role : Active device 1
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
root@GalensSynology:/volume2/homes/galenzhao# mdadm --examine /dev/sdd3
/dev/sdd3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : ce0e9aff:a0d43a65:acbf6b7f:d9786045
Name : GalensSynology:2 (local to host GalensSynology)
Creation Time : Thu Sep 26 14:46:34 2019
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 966866976 (461.04 GiB 495.04 GB)
Array Size : 483433472 (461.04 GiB 495.04 GB)
Used Dev Size : 966866944 (461.04 GiB 495.04 GB)
Data Offset : 264192 sectors
Super Offset : 8 sectors
Unused Space : before=264112 sectors, after=32 sectors
State : clean
Device UUID : 5fc2ee9a:1ea9ba1c:bc415760:777f9c01
Update Time : Thu Aug 11 22:58:51 2022
Bad Block Log : 512 entries available at offset 16 sectors
Checksum : a0624a6d - correct
Events : 1220
Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
root@GalensSynology:/volume2/homes/galenzhao# mdadm --examine /dev/sdc3
/dev/sdc3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 90e5ba00:0ac44575:d3356c1a:4949e120
Name : GalensSynology:5 (local to host GalensSynology)
Creation Time : Thu Aug 11 21:17:31 2022
Raid Level : raid1
Raid Devices : 1
Avail Dev Size : 967129120 (461.16 GiB 495.17 GB)
Array Size : 483564544 (461.16 GiB 495.17 GB)
Used Dev Size : 967129088 (461.16 GiB 495.17 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=32 sectors
State : clean
Device UUID : 72b8d726:e6002116:fc1a33af:5332d72a
Update Time : Thu Aug 11 21:20:33 2022
Checksum : 2dd6b7e2 - correct
Events : 1
Device Role : Active device 0
Array State : A ('A' == active, '.' == missing, 'R' == replacing)