How To Use SSHFS To Mount Remote File Systems Over SSH

Step 3 — Permanently Mounting the Remote Filesystem

For production environments and AI/ML workflows that require persistent access to remote data, configuring permanent SSHFS mounts is essential. This section covers both traditional /etc/fstab configuration and modern systemd-based approaches.

Traditional fstab Configuration

Basic fstab Entry

Open /etc/fstab with your preferred editor:

1. sudo nano /etc/fstab

Add a basic SSHFS entry at the end of the file:

# SSHFS mount for remote data sammy@your_other_server:~/ /mnt/remote_data fuse.sshfs noauto,x-systemd.automount,_netdev,reconnect,identityfile=/home/sammy/.ssh/id_rsa,allow_other,default_permissions 0 0

Advanced fstab Configuration for AI/ML Workflows

For data-intensive applications, use this optimized configuration:

# AI/ML Dataset Mount - Optimized for Performance sammy@gpu_server:/datasets /mnt/ml_datasets fuse.sshfs noauto,x-systemd.automount,_netdev,reconnect,identityfile=/home/sammy/.ssh/id_rsa,allow_other,default_permissions,compression=yes,cache=yes,auto_cache,ServerAliveInterval=15,ServerAliveCountMax=3 0 0 # Model Checkpoints Mount - Read/Write Access sammy@model_server:/models /mnt/model_checkpoints fuse.sshfs noauto,x-systemd.automount,_netdev,reconnect,identityfile=/home/sammy/.ssh/id_rsa,allow_other,default_permissions,compression=yes 0 0 # Shared Code Repository Mount sammy@git_server:/repos /mnt/shared_code fuse.sshfs noauto,x-systemd.automount,_netdev,reconnect,identityfile=/home/sammy/.ssh/id_rsa,allow_other,default_permissions 0 0

Configuration Options Explained:

• noauto: Prevents automatic mounting at boot
• x-systemd.automount: Enables systemd automounting (mounts on first access)
• _netdev: Indicates network dependency
• reconnect: Automatically reconnects on connection drops
• identityfile: Path to SSH private key for authentication
• compression=yes: Enables SSH compression
• cache=yes,auto_cache: Enables local caching
• ServerAliveInterval=15: Keep-alive interval
• ServerAliveCountMax=3: Maximum failed keep-alive attempts

Modern systemd-based Configuration

Creating a systemd Mount Unit

Create a systemd mount unit for better control:

1. sudo nano /etc/systemd/system/mnt-remote_data.mount

Add the following content:

[Unit] Description=SSHFS mount for remote data After=network-online.target Wants=network-online.target Before=remote-fs.target [Mount] What=sammy@your_other_server:~ Where=/mnt/remote_data Type=fuse.sshfs Options=allow_other,default_permissions,compression=yes,cache=yes,auto_cache,reconnect,IdentityFile=/home/sammy/.ssh/id_rsa [Install] WantedBy=multi-user.target

Creating a systemd Automount Unit

For on-demand mounting, create an automount unit:

1. sudo nano /etc/systemd/system/mnt-remote_data.automount

[Unit] Description=SSHFS automount for remote data After=network-online.target Wants=network-online.target [Automount] Where=/mnt/remote_data TimeoutIdleSec=300 [Install] WantedBy=multi-user.target

Enabling and Managing systemd Mounts

1. # Enable and start the automount
2. sudo systemctl enable mnt-remote_data.automount
3. sudo systemctl start mnt-remote_data.automount
4. # Check mount status
5. sudo systemctl status mnt-remote_data.automount
6. # Manually mount/unmount
7. sudo systemctl start mnt-remote_data.mount
8. sudo systemctl stop mnt-remote_data.mount

Testing Permanent Mounts

Test fstab Configuration

1. # Test fstab entries without rebooting
2. sudo mount -a
3. # Check if mounts are active
4. mount | grep sshfs
5. # Test automount functionality
6. ls /mnt/remote_data

Verify systemd Mounts

1. # Check systemd mount status
2. sudo systemctl status mnt-remote_data.mount
3. # View mount logs
4. sudo journalctl -u mnt-remote_data.mount
5. # Test automount
6. sudo systemctl status mnt-remote_data.automount

Security Considerations for Permanent Mounts

SSH Key Management

Ensure SSH keys are properly secured:

1. # Set correct permissions on SSH keys
2. chmod 600 /home/sammy/.ssh/id_rsa
3. chmod 644 /home/sammy/.ssh/id_rsa.pub
4. # Use SSH agent for key management
5. ssh-add /home/sammy/.ssh/id_rsa

Network Security

Configure SSH for optimal security:

1. # Edit SSH client config
2. nano ~/.ssh/config

Add the following configuration:

Host your_other_server HostName your_other_server User sammy Port 22 IdentityFile /home/sammy/.ssh/id_rsa ServerAliveInterval 15 ServerAliveCountMax 3 Compression yes ForwardAgent no ForwardX11 no

Troubleshooting Permanent Mounts

Common Issues and Solutions

When setting up permanent SSHFS mounts, you might encounter several issues. Here’s a breakdown of common problems and how to troubleshoot them:

1. Mount fails at boot: This often occurs if the network is not fully initialized when systemd attempts to mount the filesystem, if there are errors in the /etc/fstab entry, or if the systemd automount unit is misconfigured.

   1. # Check systemd logs for the mount unit
   2. sudo journalctl -u mnt-remote_data.mount
   3. # Test manual mount to isolate fstab/systemd issues from SSHFS command issues
   4. sudo mount /mnt/remote_data

2. Network connectivity issues: Problems connecting to the remote server can stem from incorrect server addresses, firewall restrictions (on either local or remote machine), or general network instability.

   1. # Test the underlying SSH connection independently
   2. ssh sammy@your_other_server
   3. # Check the status of your local network manager
   4. systemctl status NetworkManager

3. Permission problems: These usually arise when the local user doesn’t have the necessary permissions to access the mounted directory, if allow_other is missing, or if uid/gid mapping is incorrect, or if the IdentityFile has incorrect permissions.

   1. # Check the permissions of the local mount point
   2. ls -la /mnt/remote_data
   3. # Verify the user and group IDs of the local user
   4. id sammy

Production Considerations: While SSHFS permanent mounts work well for development and AI/ML workflows, consider the network dependency and potential performance implications. For mission-critical production systems, evaluate whether NFS or SMB might be more appropriate for your specific use case.