我正在尝试减小备份驱动器映像的大小。原始磁盘有以下分区：
Model: ST916082 1A (scsi)
Disk /dev/sde: 160GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 32.3kB 65.7GB 65.7GB primary ntfs boot
2 65.7GB 160GB 94.4GB extended lba
5 65.7GB 160GB 94.4GB logical ntfs
映像是使用以下命令从逻辑分区创建的
> sudo ddrescue /dev/sde5 datapartition logfile
Press Ctrl-C to interrupt
Initial status (read from logfile)
rescued: 0 B, errsize: 0 B, errors: 0
Current status
rescued: 94368 MB, errsize: 0 B, current rate: 23068 kB/s
ipos: 94368 MB, errors: 0, average rate: 28839 kB/s
opos: 94368 MB, time from last successful read: 0 s
Finished
ntfsresize -i -f datapartition说：
ntfsresize v2012.1.15AR.5 (libntfs-3g)
Device name : datapartition
NTFS volume version: 3.1
Cluster size : 4096 bytes
Current volume size: 26999992832 bytes (27000 MB)
Current device size: 94368605184 bytes (94369 MB)
Checking filesystem consistency ...
100.00 percent completed
Accounting clusters ...
Space in use : 26107 MB (96.7%)
Collecting resizing constraints ...
You might resize at 26106810368 bytes or 26107 MB (freeing 893 MB).
Please make a test run using both the -n and -s options before real resizing!
所以看起来我已经调整了文件系统的大小以适应数据，但没有调整设备的大小？ （这是 2 年前的事了，我忘了。）我需要使用 fdisk 调整设备大小，对吧？但 fdisk 无法识别该分区：
> fdisk -lu datapartition
Disk datapartition: 94.4 GB, 94368605184 bytes
255 heads, 63 sectors/track, 11472 cylinders, total 184313682 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 identifier: 0x69205244
This doesn't look like a partition table
Probably you selected the wrong device.
Device Boot Start End Blocks Id System
datapartition1 ? 218129509 1920119918 850995205 72 Unknown
datapartition2 ? 729050177 1273024900 271987362 74 Unknown
datapartition3 ? 168653938 168653938 0 65 Novell Netware 386
datapartition4 2692939776 2692991410 25817+ 0 Empty
Partition table entries are not in disk order
cfdisk 也不：
> cfdisk datapartition
FATAL ERROR: Bad primary partition 1: Partition begins after end-of-disk
Press any key to exit cfdisk
不过，我可以安装分区并从中复制文件。如何调整设备大小？
答案1
如果只是分区的转储，则没有分区表。分区就是文件，只需要缩小文件即可：
truncate -s 27000832000 datapartition
（为了安全起见，27000832000 是 26999992832 四舍五入到下一个 MiB，您是否希望将其压缩为某种qcow2格式或任何其他可安装的压缩格式）
