24

How to move a partition to the beginning of the disk a bit? Parted wants a filesystem for some reason (I don't know why), I want just to shift all sectors left...

r@l:15:32:45:~# parted /dev/sdb
GNU Parted 2.3
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p                                                                
Model: HGST HTS 541010A9E680 (scsi)
Disk /dev/sdb: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      1049kB  32.2GB  32.2GB  primary  fat32
 2      32.2GB  37.6GB  5360MB  primary
 3      37.6GB  1000GB  963GB   primary

(parted) move 3                                                           
WARNING: you are attempting to use parted to operate on (move) a file system.
parted's file system manipulation code is not as robust as what you'll find in
dedicated, file-system-specific packages like e2fsprogs.  We recommend
you use parted only to manipulate partition tables, whenever possible.
Support for performing most operations on most types of file systems
will be removed in an upcoming release.
Error: Could not detect file system.
Hennes
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Vi.
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3 Answers3

17

Manual way with dd and fdisk:

# fdisk -l /dev/sdb | grep sdb3
/dev/sdb3        73402368  1953525167   940061400   83  Linux

# fdisk /dev/sdb
Command (m for help): d
Partition number (1-4): 3
Command (m for help): n
Partition number (1-4, default 3): 3
First sector (73385984-1953525167, default 73385984): 
Using default value 73385984
Last sector, +sectors or +size{K,M,G} (73385984-1953525167, default 1953525167): 
Using default value 1953525167
Command (m for help): w
The partition table has been altered!

# fdisk -l /dev/sdb | grep sdb3
/dev/sdb3        73385984  1953525167   940069592   83  Linux

# dd conv=notrunc bs=512 iflag=fullblock if=/dev/sdb3 count=100 skip=$((73402368-73385984)) seek=0 2> /dev/null | file -s -
/dev/stdin: LUKS encrypted file, ver 1 [aes, cbc-essiv:sha256, sha1] UUID: af1c47f0-4ca5-4ea7-a091-065bd263653f

# dd conv=notrunc bs=512 iflag=fullblock if=/dev/sdb3  skip=$((73402368-73385984)) seek=0 of=/dev/sdb3

# file -s /dev/sdb3
/dev/sdb3: sticky LUKS encrypted file, ver 1 [aes, cbc-essiv:sha256, sha1] UUID: af1c47f0-4ca5-4ea7-a091-065bd263653f

Now waiting for about 2h. (more looks more like 18h...)

Note: this only moves data back, not forward.

Pausing:

# pidof dd
907
# kill -STOP 907
# cat /proc/907/fdinfo/1
pos:    586921398272
flags:  0100001

# kill -9 907

remember 586921398272/512 = 1146330856

Resuming:

dd conv=notrunc bs=512 iflag=fullblock if=/dev/sdb3  skip=$((1146330856+73402368-73385984)) seek=1146330856 of=/dev/sdb3
Vi.
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16

sfdisk, which intents to be a scriptable fdisk, has since some version the --move-data option. Example from their man page:

echo '+100M,' | sfdisk --move-data /dev/sdc -N 1
gimpf
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5

You can always use dd.

  • Boot from a liveCD (or any other way which makes sure the partition is not mounted)
  • dd if=/dev/sdc2 of=somefile bs=1M to create a copy of the partition on a file.
  • fdisk (or whatever you like) to delete the partition
  • fdisk (or whatever you like) to create the partition in your desired place.
  • dd of=/dev/sdc2 if=somefile bs=1M to restore the contents from file.
Hennes
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