FDisk Basics

1sudo fdisk /dev/sda

• m for help.

• n to make a partition.

• t to mark the partition type (see IDs below).

• w to write the changes to the disk.

Note the asterisk marking the boot partition.

IDs

fdisk will not help with a GPT formatted drive. For this, use gdisk, which is mostly the same.

Now that we have a partition, we can make it into a fileSystem. Most will use:

1sudo mkfs -t ext4 /dev/sdc1

or if you're making a swap partition, you can use:

1sudo mkswap /dev/sdb2

or for the reiser fileSystem, we can use:

1sudo mkreiserfs /dev/sdc2

File System Types

Parted

1sudo parted /dev/sdb

Monitoring

Look at physical and virtual partitions:

1df -h

or divide things by inode - the thing which records where files are?

1df -i

Examine a fileSystem with:

1sudo dumpe2fs /dev/sda1 | less

Prevention

There are multiple programs which work mostly the same way.

1sudo tune2fs -c 30 /dev/sda1

This will check sda1 every 30 boots. It can also be checked every month.

1sudo tune2fs -i 1m /dev/sda1

This thing can also make a new label for the System:

1sudo tune2fs -L new_name /dev/sdb3

Repair

Start by unmounting the fileSystem.

1sudo umount /dev/sdc1

Then it's time to check.

1sudo fsck /dev/sdc1

And possibly repair damage:

1e2fsck -p /dev/sdc1

or the same with:

1sudo debugfs /dev/sdc1

Mounting

You can mount with a specified filetype with:

1sudo mount -t ext3 /dev/sdc2 /mnt/stick

or if you don't know the type, just try the lot:

1sudo mount -a /dev/sdc1 /mnt/stick

File Systems

xfs and zfs can only be expanded.

Shrink FileSystem

NB: When I followed these instructions, the process destroyed my data. Seemed fine on the YouTube video.

Check the fileSystem's health:

1sudo e2fsck -f /dev/sdb1

Resize the file System to something smaller than what you want, so here I want 500G and so I resize to 450 G.

1resize2fs /dev/sdb1 450G

Then delete the partition with either gdisk or fdisk, depending upon the layout.

1sudo fdisk /dev/sdb

1d

Then make a new fileSystem of the desired type with:

1n

And finally resize to the full size you want:

sudo resize2fs /dev/sdb1

And then check your disk again with e2fsck.

(The e2fsck saved my disk in the end, YMMV)

Logical Volume

Let's start with names. PV = 'Physical Volume', VG = 'Volume Group', and LV = 'Logical Volume'.

Now we can create a volume group out of sdb2 and sdc3:

1sudo vgcreate my-new-vg /dev/sdb2 /dev/sdc3

Then make a new logical volume out of the volume group:

1sudo lvcreate -n my-new-lv my-new-vg

Then have a look at all logical volumes:

1sudo lvscan