Disk management
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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 |
