mount Command

The mount command attaches filesystems to the Linux directory tree, making files and directories accessible. It's essential for accessing storage devices, network shares, and special filesystems.

Syntax

mount [options] device directory
mount [options] | directory | device
mount -a [options]

Basic Usage

Mount a device:

mount /dev/sda1 /mnt/data

Mount with specific options:

mount -o ro /dev/sda1 /mnt/data

Mount all filesystems from /etc/fstab:

mount -a

Common Filesystem Types

Type	Description	Example
`ext4`	Linux Extended Filesystem 4	`mount -t ext4 /dev/sda1 /mnt`
`xfs`	XFS Filesystem	`mount -t xfs /dev/sda1 /mnt`
`ntfs`	Windows NTFS	`mount -t ntfs /dev/sda1 /mnt`
`vfat`	FAT32/VFAT	`mount -t vfat /dev/sda1 /mnt`
`iso9660`	CD/DVD ISO	`mount -t iso9660 /dev/cdrom /mnt`
`nfs`	Network File System	`mount -t nfs server:/share /mnt`
`cifs`	Windows/Samba Share	`mount -t cifs //server/share /mnt`
`tmpfs`	Temporary Filesystem	`mount -t tmpfs tmpfs /tmp`
`proc`	Process Information	`mount -t proc proc /proc`
`sysfs`	System Information	`mount -t sysfs sysfs /sys`

Mount Options

Read/Write Options

Option	Description
`ro`	Read-only
`rw`	Read-write (default)
`sync`	Synchronous I/O
`async`	Asynchronous I/O (default)
`remount`	Remount with different options

Filesystem Behavior

Option	Description
`atime`	Update access time on read (default)
`noatime`	Don't update access time
`relatime`	Update access time relative to modification
`nodiratime`	Don't update directory access time

User and Security Options

Option	Description
`user`	Allow any user to mount/unmount
`users`	Allow any user to mount, any user to unmount
`nouser`	Only root can mount (default)
`exec`	Allow execution of binaries (default)
`noexec`	Don't allow execution of binaries
`suid`	Honor setuid and setgid bits (default)
`nosuid`	Ignore setuid and setgid bits
`dev`	Honor device files (default)
`nodev`	Ignore device files

Performance Options

Option	Description
`defaults`	Default options: rw, suid, dev, exec, auto, nouser, async
`auto`	Mount automatically at boot
`noauto`	Don't mount automatically
`noatime`	Improve performance by not updating access time

Usage Examples

Basic Mounting

Mount hard disk partition:

mount /dev/sdb1 /mnt/backup

Mount USB drive:

mount /dev/sdb1 /media/usb

Mount with read-only access:

mount -o ro /dev/sdb1 /mnt/readonly

Mount with specific user:

mount -o uid=1000,gid=1000 /dev/sdb1 /mnt/userdata

Special Mounts

Mount ISO image:

mount -o loop image.iso /mnt/cdrom

Mount swap file as loop device:

mount -o loop /swapfile /mnt/swap

Mount tmpfs in memory:

mount -t tmpfs -o size=1G tmpfs /tmp

Mount with specific filesystem type:

mount -t ext4 /dev/sda1 /mnt/data

Network Mounts

Mount NFS share:

mount -t nfs server:/path/to/share /mnt/nfs

Mount NFS with options:

mount -t nfs -o rsize=8192,wsize=8192 server:/share /mnt/nfs

Mount Windows/Samba share:

mount -t cifs //server/share /mnt/smb -o username=user,password=pass

Mount WebDAV share:

mount -t davfs https://webdav.example.com /mnt/webdav

Remounting

Remount as read-only:

mount -o remount,ro /mnt/data

Remount as read-write:

mount -o remount,rw /mnt/data

Remount with different options:

mount -o remount,noatime /mnt/data

/etc/fstab Configuration

fstab format:

device         mountpoint     fstype     options      dump  pass
/dev/sda1      /              ext4       defaults     0     1
/dev/sda2      /home          ext4       defaults     0     2

Common fstab entries:

Standard Linux partition:

/dev/sda1      /data          ext4       defaults,noatime 0 2

Windows partition:

/dev/sdb1      /windows       ntfs-3g    defaults,uid=1000,gid=1000 0 0

USB drive:

/dev/sdc1      /media/usb     vfat       defaults,user,utf8,uid=1000,gid=1000 0 0

Network share:

server:/share  /mnt/nfs       nfs        defaults 0 0

Temporary filesystem:

tmpfs          /tmp           tmpfs      defaults,size=2G 0 0

Advanced Options

Bind Mounts

Create bind mount:

mount --bind /source/path /dest/path

Make bind mount read-only:

mount --bind /source/path /dest/path -o ro

Bind mount in fstab:

/source/path   /dest/path     none       bind      0 0

Overlay Mounts

Create overlay filesystem:

mount -t overlay overlay \
  -o lowerdir=/lower,upperdir=/upper,workdir=/work \
  /merged

Mount by Label or UUID

Mount by label:

mount -L DATA /mnt/data

Mount by UUID:

mount -U 1234-5678 /mnt/data

Find filesystem UUID:

blkid /dev/sda1
ls -l /dev/disk/by-uuid/

Troubleshooting

Common Issues

Device busy:

# Find processes using the mount
lsof /mnt/data
fuser -m /mnt/data

# Force unmount (may cause data loss)
umount -l /mnt/data

Permission denied:

# Check mount point permissions
ls -la /mnt/data

# Mount with specific permissions
mount -o uid=1000,gid=1000 /dev/sdb1 /mnt/data

Unknown filesystem type:

# Install required filesystem drivers
sudo apt-get install ntfs-3g  # for NTFS
sudo apt-get install nfs-common  # for NFS

Finding Mount Information

List all mounts:

mount
mount | grep /mnt

Show mount details:

findmnt /mnt/data
mount -l | grep /mnt/data

Check available filesystems:

cat /proc/filesystems

List block devices:

lsblk
fdisk -l

Security Considerations

Secure Mounting Options

User data directory:

mount -o noexec,nosuid,nodev /home/user

Temporary directories:

mount -o noexec,nosuid,nodev /tmp
mount -o noexec,nosuid,nodev /var/tmp

Removable media:

mount -o nosuid,nodev,noexec /media/usb

Encryption and Security

Encrypted filesystem:

cryptsetup open /dev/sdb1 crypt_data
mount /dev/mapper/crypt_data /mnt/data

Mount with nosuid for security:

mount -o nosuid /dev/sdb1 /mnt/data

Performance Optimization

SSD Optimization

Mount SSD with noatime:

/dev/sda1      /              ext4       defaults,noatime,discard 0 1

Disable journaling for performance:

mount -o data=writeback /dev/sda1 /mnt/data

Database Optimization

Database data directory:

mount -o noatime,nodiratime,data=writeback /var/lib/mysql

Best Practices

Always use /etc/fstab for permanent mounts
Test mounts first before adding to fstab
Use appropriate options for security and performance
Monitor mount usage with df -h and mount
Backup important data before mounting
Use UUIDs instead of device names in fstab
Test automatic mounts after reboot

Integration with systemd

Mount unit files:

[Unit]
Description=Data Mount
After=network.target

[Mount]
What=/dev/sdb1
Where=/mnt/data
Type=ext4
Options=defaults

[Install]
WantedBy=multi-user.target

Enable mount unit:

systemctl enable mnt-data.mount
systemctl start mnt-data.mount

Content adapted from the linux-command project. Original content available at https://github.com/jaywcjlove/linux-command

Syntax​

Basic Usage​

Common Filesystem Types​

Mount Options​

Read/Write Options​

Filesystem Behavior​

User and Security Options​

Performance Options​

Usage Examples​

Basic Mounting​

Special Mounts​

Network Mounts​

Remounting​

/etc/fstab Configuration​

Advanced Options​

Bind Mounts​

Overlay Mounts​

Mount by Label or UUID​

Troubleshooting​

Common Issues​

Finding Mount Information​

Security Considerations​

Secure Mounting Options​

Encryption and Security​

Performance Optimization​

SSD Optimization​

Database Optimization​

Best Practices​

Integration with systemd​