drivemap - Online in the Cloud

PROGRAM:

NAME

drivemap - show block devices in a tree of dependencies

SYNOPSIS

drivemap [-i|--info [-w|--width N]] [-d|--drive] [FILE]
drivemap [-i|--info [-w|--width N]] [-p|--mountpoint] [-f|--backing-file] [-n|--dm-name]
[-m|--mark] [FILE]

drivemap -h|--help
drivemap [--debug] [-x|--set-x] [OPTIONS] [FILE]

DESCRIPTION

drivemap is a shell script using the proc, sysfs and udev databases to display block
devices in a tree of dependencies. It is based on bilibop-common shell functions and
supports device-mapper (including dm-crypt and LVM) and loop devices, with some
limitations. RAID devices and mhddfs filesystems are not supported. See the ENHANCEMENTS
AND LIMITATIONS section below.

OPTIONS

When no FILE argument is invoked, the command is applied to all drives. If a FILE is given
as argument and exists, then the command applies to the drive hosting it. FILE can be a
regular file, a directory or a block device.

--debug
Display debug information on stderr. When this option is invoked, each called
function prints its name. See also '--set-x'.

-d, --drive
Only show the drive node instead of its tree.

-f, --backing-file
Try to replace each loop device in the tree by its backing file. This can fail in
some cases: for example on DebianLive systems, a loop device is associated to
filesystem.squashfs from into the initramfs environment; the path of the backing
file in /sys is not updated when the squashfs itself becomes the new root
filesystem. And so the filename stored in backing_file is obsolete, and will not
be displayed here.

-h, --help
Print a summary of options on stdout and exit.

-i, --info
Display additional information about block devices. For drives, this includes the
ID (as found in /dev/disk/by-id), and the size (human readable). For other devices
(partitions and virtual block devices), this includes the filesystem type ant its
size.

-m, --mark
If a FILE is given as argument, append a mark (a star between parenthesis: (*)) to
the name of the device hosting this FILE. Otherwise, append a mark to the name of
the device hosting the current working directory.

-n, --dm-name
Replace device-mapper nodes (/dev/dm-*) by device-mapper names (/dev/mapper/*),
which are statically attributed and generally easier to understand.

-p, --mountpoint
Show the mountpoints of mounted devices, and show swap devices in use.

-w N, --width=N
Format the output on N columns. Can be used with '--info' and/or '--mountpoint'.
If N is not an integer or is greater than the number of columns of the screen, then
the output will use the full width of the screen. If this option is not used, then
the default is to display the result on 70 columns.

-x, --set-x
Display debug information on stderr. When this option is invoked, the shell script
is set as -x, for more debug details. See also '--debug'.

ENHANCEMENTS AND LIMITATIONS

drivemap is a part of the bilibop(7) project. It has initially been written to be applied
to the external drive hosting the running system. By design, it don't support RAID
devices, and will never support them. Another design issue is that lvm(8) Volume Groups
should contain only one Physical Volume. We assume that there is no sense to use several
Physical Volumes on the same drive for the same Volume Group. Adopting a parent/child
mindview, we say that each device can have at most one parent but zero to several
children. Since the script has been extended to be applied to all drives connected to the
computer, this sounds like a bug.

Unlike the lsblk(1) command, drivemap integrates loopback devices in the tree of
dependencies. In fact, the question that can be asked is the following:
" What will happen to the content of other physical or virtual block devices if I dd(1),
shred(1) or wipe(1) this one or this one ? "
And then it appears that slaves and holders information in sysfs are not sufficient to
organize block devices in a tree, or should be extended. For the same reason, logical
partitions are shown as subdevices of primary extended partitions.

Only block devices whose contents is hosted by a physical disk are shown: this means if a
loop device is associated to a file residing on a temporary filesystem (tmpfs, i.e. the
RAM), this device will not be shown. This is NOT a bug: as said by its name, drivemap
builts and displays a 'map of drive(s)'.

EXAMPLES

List the physical drives actually known by the kernel:

drivemap -d

Find the drive hosting the running system, and display its ID and size:

drivemap -id /

Show where is my current working directory on a disk with a complex partition scheme (LVM
+ LUKS + LVM):

drivemap -min .

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