我使用 5 个 4TB 驱动器创建了软件 RAID 6 mdadm --create /dev/md0 --chunk=256 --level=6 --raid-devices=5 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1。在此之前，我已经在每个驱动器上创建了最大大小的分区。 “fdisk -l”显示以下输出。不过整体大小只有6TB。由于 Raid 6 有 2 个奇偶校验，难道不应该有 12TB 左右吗？
Disk /dev/sda: 525.1 GB, 525112713216 bytes, 1025610768 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
Disk label type: gpt
# Start End Size Type Name
1 46139392 83888127 18G Microsoft basic
2 8390656 46139391 18G Microsoft basic
3 87033856 1025610734 447.6G Linux LVM
4 83888128 84936703 512M BIOS boot parti
5 2048 8390655 4G Microsoft basic
6 84936704 87033855 1G Linux swap
Disk /dev/sdb: 4000.8 GB, 4000787030016 bytes, 7814037168 sectors
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 label type: dos
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdb1 1 4294967295 2147483647+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/sdc: 4000.8 GB, 4000787030016 bytes, 7814037168 sectors
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 label type: dos
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdc1 1 4294967295 2147483647+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/sde: 4000.8 GB, 4000787030016 bytes, 7814037168 sectors
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 label type: dos
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sde1 1 4294967295 2147483647+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/sdd: 4000.8 GB, 4000787030016 bytes, 7814037168 sectors
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 label type: dos
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdd1 1 4294967295 2147483647+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/sdf: 4000.8 GB, 4000787030016 bytes, 7814037168 sectors
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 label type: dos
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdf1 1 4294967295 2147483647+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/mapper/XSLocalEXT--b30a297a--410a--d586--640b--e10ac011aaf3-b30a297a--410a--d586--640b--e10ac011aaf3: 480.5 GB, 480537214976 bytes, 938549248 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
答案1
您的分区比完整磁盘小得多：
/dev/sdc1 1 4294967295 2147483647+ ee GPT
仅占用 4294967295 个扇区（7814037168 个扇区），IE略低于 2TiB。
如果您打算在 RAID 阵列中使用整个磁盘，我建议您只使用整个磁盘，而不用担心分区。首先，将任何看起来像超级块的东西归零md：
mdadm --zero-superblock /dev/sdb
mdadm --zero-superblock /dev/sdc
mdadm --zero-superblock /dev/sdd
mdadm --zero-superblock /dev/sde
mdadm --zero-superblock /dev/sdf
然后创建数组：
mdadm --create /dev/md0 --chunk=256 --level=6 --raid-devices=5 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf
如果您希望允许用扇区数稍少的驱动器替换出现故障的驱动器，您可能需要留出一些可用空间；您可以使用--size=需要大小（要占用的磁盘空间量）的选项来执行此操作使用）以千字节为单位，例如在您的情况下，大约为 3,907,018,300KiB（您的驱动器有 3,907,018,584KiB 总空间，其中 128KiB 需要保留用于 RAID 超级块）。