Disk management

The following are common Linux commands for disk management.

1 Disk management

Command	Function
badblocks -s /dev/sda	Test for unreadable blocks on disk /dev/sda
df -h	Show free and used space on mounted file systems in human-readable format
df -i	Shows free inodes of mounted file systems; inodes contain information on disk block locations and other attributes.
du -ah	Display disk usage for all files and directories in human readable format
du -hs	Display the size of the current directory
du -s	Give important information regarding the disk usage (storage space) on your Linux system. It is efficient when combined with the Sudo command.
du -sh	Display the currently active directory's disk usage
eject	Eject a disk
fdisk -l	Display all disk partitions sizes and types
fdisk -l	Edit a disk partition
fdisk /dev/sda	Create a new partition on /dev/sda
file -b -i	Helps identify the type of file on your system.
findmnt	Displays the mount points associated with all file systems
fsck	File check and repair
fsck -A -N	Check and repair a file system.
fsck.ext4 /dev/sda1	Check and repair a filesystem for errors
hdparm -tT /dev/sda	Perform a read speed test on disk /dev/sda
lsblk	Display information about block devices
lsusb	Display USB ports and devices
lsusb -tv	Display all USB devices
lvcreate	Create a logical volume.
lvcreate	Create a logical volume
md5sum	Calculate md5sum
mkfs -t -V	Create a new file system.
mkfs -t [partition-type] -c -v [/partition]	Formats partition with the specified filesystem
mkfs -t xfs -c -v /home	Creates xfs partition as /home; -v = verbose, -c = check for bad blocks
mkfs.ext4 /dev/sda1	Format the partition /dev/sda1
mkswap /dev/sda5	Create swap on sda5
mount	Mount partition
mount -a -t	Mount a file system.
mount -a /etc/fstab	Mount all file systems listed in fstab
mount -t type /dev/sda	Mount partition by type
mount /dev/sda1 /mnt	Mount a partition to a directory
mount device_path mount_point	Mount a device.
pvcreate	Create a physical volume.
swapon /dev/sda5	Activate swap on sda5
umount	Unmount a partition
umount -l	Lazy unmount; immediately unmount and clean up later
unmount -f -v	Unmount a mounted file system.

2 Disk errors

Disk errors may cause boot issues. Sometimes these can be dealt with the file repair command for the.

fsck /dev/sda1
e2fsck /dev/sda1 [specifically for ext filesystems]

Errors with magic numbers in superblocks can be more difficult. One must first query the locations of the superblocks on the device like so.

mke2fs -n /dev/sda

This outputs a list of superblock locations. The one needs to manually try to rebuild the superblocks by entering the following repair command with each superblock number, until a usable superblock is found. Usually one needs to try this with each superblock location, one by one, from the mke2fs output, until the right one is found.

e2fsck -b 32768 /dev/sda1

3 RAID disk management

Command	Function
lsblk -o name, fstype, mountpoint	Find devices constituting a RAID array
mdadm --create /dev/md0 --level=1 /dev/sda1 /dev/sdb1	Create RAID array, level 1, with sda + sdb
mdadm --remove /dev/md0	Remove RAID array
mdadm --scan --assemble –uuid=UUID	Scan RAID array
mdadm --stop /dev/md0	Stop RAID array
mdadm –assemble [device names]	Assemble RAID array