我有一个RAIDADMconfiguration中有四个1TB磁盘的MDADMarrays。 这里是mdadm --detail /dev/md1的相关部分mdadm --detail /dev/md1 ：
Version : 00.90 Raid Level : raid5 Array Size : 2929537920 (2793.83 GiB 2999.85 GB) Used Dev Size : 976512640 (931.28 GiB 999.95 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Persistence : Superblock is persistent
这表明arrays是2.8TB。 这里是fdisk -l /dev/md1 ：
Disk /dev/md1: 2999.8 GB, 2999846830080 bytes 2 heads, 4 sectors/track, 732384480 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 65536 bytes / 196608 bytes Disk identifier: 0xffffffff Disk /dev/md1 doesn't contain a valid partition table
fdisk也显示它是3TB。 但是， df -Th不同意：
Filesystem Type Size Used Avail Use% Mounted on /dev/md1 ext3 1.8T 1.8T 0 100% /
为什么一切显示/dev/md1是3TB，但空间仅限于2TB？
其他细节：Ubuntu 10.10
更新：
$ tune2fs -l /dev/md1 ：
tune2fs 1.41.12 (17-May-2010) Filesystem volume name: <none> Last mounted on: <not available> Filesystem UUID: 1b4e9420-61ee-4ffd-817a-28831f2aeaf2 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super large_file Filesystem flags: signed_directory_hash Default mount options: (none) Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 122068992 Block count: 488255968 Reserved block count: 24412798 Free blocks: 69746292 Free inodes: 121882953 First block: 0 Block size: 4096 Fragment size: 4096 Reserved GDT blocks: 907 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 RAID stride: 16 RAID stripe width: 32 Filesystem created: Sun Oct 17 01:14:23 2010 Last mount time: Mon Dec 6 01:24:31 2010 Last write time: Mon Dec 6 00:45:41 2010 Mount count: 12 Maximum mount count: 23 Last checked: Sun Dec 5 20:37:35 2010 Check interval: 15552000 (6 months) Next check after: Fri Jun 3 21:37:35 2011 Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 First orphan inode: 55550208 Default directory hash: half_md4 Directory Hash Seed: 2a386fcb-b24f-4f40-bf4c-7c03489b086c Journal backup: inode blocks
你创build文件系统后添加了第四个驱动器？ 这可能导致FS比底层设备小。
另外，也许你的ext3有1k块，因为这将导致2TB的文件系统大小限制（ ext3大小限制 ）。
请发布“sudo tune2fs -l / dev / md1”的输出，并仔细查看块大小行。