Debian掛載高級技巧分享

Here are some advanced mounting techniques for Debian, covering network mounts, encryption, performance optimization, and special file systems:

1. Network File System (NFS/Samba) Mounts

Debian supports mounting remote file systems via NFS (for Linux/Unix) or Samba (for Windows).

• NFS Mount: Install nfs-common first, then mount a remote export:

  sudo apt install nfs-common
  sudo mount -t nfs server:/path/to/export /mnt/nfs
  

• Samba Mount: Install cifs-utils, then mount a Windows share (replace credentials with your own):

  sudo apt install cifs-utils
  sudo mount -t cifs //server/share /mnt/samba -o username=user,password=pass,domain=domain
  

• Auto-Mount: Add entries to /etc/fstab for persistent mounting (e.g., server:/export /mnt/nfs nfs defaults 0 0).

2. Bind Mounts

Bind mounts link a directory to another location, making their contents identical. This is useful for sharing directories between containers or users.

sudo mount --bind /source/directory /destination/directory

To make it persistent, add to /etc/fstab:

/source/directory /destination/directory none bind 0 0

3. OverlayFS

OverlayFS merges two directories (lowerdir: base, upperdir: changes) into a virtual filesystem. Commonly used in Docker for layered images.

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

• Parameters:
  • lowerdir: Read-only base layer.
  • upperdir: Writable layer for changes.
  • workdir: Temporary workspace for OverlayFS.
• Auto-Mount: Add to /etc/fstab with the same options.

4. Tmpfs (RAM-Based Filesystem)

Tmpfs stores files in memory (volatile), ideal for temporary data (e.g., /tmp).

sudo mount -t tmpfs -o size=512M tmpfs /mnt/tmpfs

• Options:
  • size: Limit RAM usage (e.g., 512M).
  • noexec: Prevent execution of binaries.
• Auto-Mount: Add to /etc/fstab:

  tmpfs /mnt/tmpfs tmpfs defaults,size=512M 0 0
  

5. Encrypted Partitions (LUKS)

LUKS (Linux Unified Key Setup) encrypts partitions for security.

• Step 1: Install cryptsetup and format the partition (WARNING: this erases data):

  sudo apt install cryptsetup
  sudo cryptsetup luksFormat /dev/sdXn
  

• Step 2: Open the encrypted partition and mount it:

  sudo cryptsetup open /dev/sdXn my_encrypted
  sudo mount /dev/mapper/my_encrypted /mnt/encrypted
  

• Auto-Mount:
  • Edit /etc/crypttab to link the encrypted partition to a mapper name:

    my_encrypted /dev/sdXn none luks
    

  • Add to /etc/fstab to mount the decrypted device:

    /dev/mapper/my_encrypted /mnt/encrypted ext4 defaults 0 2
    

6. Mount Optimization Options

Improve performance with these mount options:

• noatime: Disables updating file access times (reduces disk I/O). Example:

  sudo mount -o noatime /dev/sdXn /mnt/data
  

• relatime: Updates access time only if it’s older than modification time (default in newer kernels).
• data=writeback: Improves write performance for ext4 by delaying metadata updates (use with caution for critical data).
• Auto-Mount: Add options to /etc/fstab (e.g., defaults,noatime).

7. Automount with autofs

autofs mounts filesystems on-demand (when accessed) and unmounts them after inactivity, saving resources.

• Install autofs:

  sudo apt install autofs
  

• Configure: Edit /etc/auto.master to define a mount point (e.g., /mnt/nfs) and /etc/auto.nfs to specify the remote share:

  /mnt/nfs -fstype=nfs server:/path/to/export
  

• Restart autofs:

  sudo systemctl restart autofs
  

Now, accessing /mnt/nfs will trigger the mount automatically.