Restic NAS Backup Failed? Fix Repository Not Found Error!

Nov 16, 2025 by Admin 58 views

Hey there, tech enthusiasts and fellow data hoarders! Ever woken up to find your precious Restic NAS backup service failed, throwing that dreaded "repository does not exist" error? Man, it can be a real headache, right? Especially when you're relying on restic-backups-nas.service to keep your Network Attached Storage (NAS) data safe and sound. If you've encountered a restic-backups-nas.service failure on your storage host, specifically with exit code 10 and the message Fatal: repository does not exist: unable to open config file: stat /mnt/data/backups/restic/config: no such file or directory, you're in the right place. We're going to dive deep into why this happens and, more importantly, how to fix it so your backups are back on track. This isn't just about a quick fix; it's about understanding the underlying problem to prevent future mishaps, especially for you NixOS users out there. Let's get our hands dirty and make sure your data is super secure!

Understanding the Restic Service Failure: "Repository Does Not Exist"

When your restic-backups-nas.service bombs out with the infamous "repository does not exist" message, it's basically Restic telling you, "Hey, I can't find the place where I'm supposed to store or retrieve your backups!" The log snippet, Fatal: repository does not exist: unable to open config file: stat /mnt/data/backups/restic/config: no such file or directory, is the smoking gun. It clearly points to a missing config file within the /mnt/data/backups/restic directory. This config file is absolutely crucial because it contains all the metadata and setup information for your Restic repository. Without it, Restic has no idea where to put your data or how to encrypt it, making any backup attempt futile. The restic-backups-nas.service tries to execute restic backup, but since its target repository isn't there or isn't properly initialized, it fails immediately, resulting in exit code 10. This isn't just a transient glitch; it's a fundamental issue with your repository's presence or accessibility.

Think of it like this: you've told a librarian (Restic) to put a book (your data) into a specific shelf (the repository at /mnt/data/backups/restic). But when the librarian goes to the shelf, it's either completely gone, or it's not set up yet, or they can't even get to it. That's essentially what this error means. The restic-backups-nas.service is configured to interact with a repository at a very specific path, /mnt/data/backups/restic. If this path is empty, unmounted, or if the restic init command was never run there, Restic simply cannot proceed. This failure is often triggered by the restic-backups-nas.timer, meaning it's a scheduled job that consistently fails. This persistence is why the intelligent filtering system flagged it as a significant problem, as noted in the service failure report. A successful Restic repository always has a config file along with data, index, keys, and snapshots directories once it's initialized. The absence of the config file is the clearest indicator that the repository either got corrupted, deleted, or was never properly set up in the first place. So, our primary goal, guys, is to make sure that restic has a valid, accessible repository at that exact location. We'll start by checking the simplest things and then move to more complex solutions to resolve this restic-backups-nas.service headache. Remember, systemd is just doing its job, trying to run your backup service, but it needs a solid foundation to work from!

Initial Checks and Quick Fixes for Your Restic NAS Backup

Alright, folks, let's get down to business with some initial checks and quick fixes for this pesky restic-backups-nas.service failure. Before we dive into complex solutions, we need to cover the basics. Often, the simplest things are overlooked, and they're usually the easiest to resolve. Our main keyword here is Restic NAS backup, and we're zeroing in on that "repository does not exist" error.

First things first, let's make sure the target directory for your Restic repository, /mnt/data/backups/restic, is actually there and accessible. This might sound super obvious, but trust me, it’s a common culprit!

Verify the Mount Point: Is /mnt/data properly mounted? On a NAS, this is crucial. If your network share or local disk isn't mounted where it's supposed to be, Restic won't see anything.
- Open your terminal and type: ls -la /mnt/data/backups/restic
- If you get an error like "No such file or directory" or if the output is completely empty when you expect to see Restic repository files, then you've found a major clue!
- Also, check mount | grep /mnt/data to confirm the drive is mounted. If it's not mounted, then restic-backups-nas.service will definitely fail. Sometimes, network issues or a reboot can cause a mount point to not come up correctly. You might need to manually mount it using sudo mount -a or by specific mount command like sudo mount /dev/your_disk_partition /mnt/data (adjusting /dev/your_disk_partition to your actual device).
Check for Typo or Configuration Error: Double-check your Restic service configuration. Is the path /mnt/data/backups/restic exactly what you intend? A tiny typo can cause hours of head-scratching. If you're using NixOS (which was mentioned in the discussion category), ensure your configuration.nix or related service definition has the correct RESTIC_REPOSITORY environment variable or command-line path specified.
- You can typically find this in the ExecStart line of your restic-backups-nas.service unit file, or in any environment variables set for it. Looking at the error log, the ExecStart command is /nix/store/v0nssfmagban50qs1f4yxd968rd8fhs3-restic-0.18.0/bin/restic backup --exclude-file=/nix/store/xz2b3ah77lqpxdci872hngpf8irzsvl3-exclude-patterns --files-from=/run/restic-backups-nas/includes. Wait a minute! The RESTIC_REPOSITORY environment variable is missing here, which is how Restic usually knows where to find the repo. This is a major red flag for your restic-backups-nas.service.
Environment Variable Check: Restic really loves its RESTIC_REPOSITORY and RESTIC_PASSWORD environment variables. The log doesn't explicitly show them being set. For your restic-backups-nas.service, you need to ensure these are passed correctly to the restic command.
- You might need to edit your restic-backups-nas.service file (or its NixOS equivalent) to include Environment=RESTIC_REPOSITORY=/mnt/data/backups/restic and Environment=RESTIC_PASSWORD_FILE=/path/to/your/password_file (or Environment=RESTIC_PASSWORD=your_password for testing, though a file is more secure).
- Without RESTIC_REPOSITORY explicitly defined, restic might not know which repository it's supposed to operate on, even if the directory exists. This is a critical point for solving your restic-backups-nas.service failure.

After making any changes, always remember to reload systemd and restart your service:

sudo systemctl daemon-reload
sudo systemctl restart restic-backups-nas.service
Then check its status: systemctl status restic-backups-nas.service

These initial checks, especially verifying the mount point and ensuring the RESTIC_REPOSITORY environment variable is correctly set and passed to your restic-backups-nas.service, will often resolve the "repository does not exist" error for your Restic NAS backup. Don't underestimate the power of these basic troubleshooting steps before moving on to more involved solutions!

Creating or Initializing the Restic Repository

Alright, guys, if your initial checks didn't magically fix the "repository does not exist" error for your restic-backups-nas.service, it's quite possible that the Restic repository itself is either truly missing or was never properly initialized at /mnt/data/backups/restic. This is a super common scenario, especially if you're setting things up for the first time, or if a catastrophic event wiped out your previous repository structure. Remember, Restic needs that config file to even know it's a repository, and if it's not there, the restic-backups-nas.service will keep failing. Our goal here is to either verify the existence of the repository or create a brand-new one if necessary, ensuring your Restic NAS backup system has a solid foundation.

First, let's verify what's actually in that directory. Navigate to your supposed repository location: cd /mnt/data/backups/restic Then list its contents: ls -la

A properly initialized Restic repository will usually contain directories like data/, index/, keys/, snapshots/, and crucially, a config file. If you don't see config or these other directories, then bingo, your repository is indeed missing or corrupted.

If the repository is missing or empty, you need to initialize it. This is where the restic init command comes into play. Be careful: only run restic init if you are absolutely sure there is no existing, valuable repository at that location. Running init on an existing repository will overwrite its configuration and effectively destroy your previous backups!

Here's how to properly initialize a new Restic repository for your restic-backups-nas.service:

Ensure the directory exists and is accessible: sudo mkdir -p /mnt/data/backups/restic sudo chown youruser:yourgroup /mnt/data/backups/restic (Replace youruser:yourgroup with the user/group that restic-backups-nas.service runs as, typically root or a dedicated backup user. If running as root, this chown might not be strictly necessary, but good practice for dedicated users). This step is vital because Restic needs to be able to write to this location. If the service user doesn't have permissions, even an init will fail.
Initialize the repository: You'll need to set the RESTIC_REPOSITORY environment variable before running restic init, just like we discussed for the restic backup command. You'll also need to set a password for your repository. This password is critical; if you lose it, your backups are inaccessible. Store it securely! Using a password file is generally recommended for automated services.

Using environment variables directly: export RESTIC_REPOSITORY=/mnt/data/backups/restic export RESTIC_PASSWORD="your_super_secret_password" (or ideally, point to a file: export RESTIC_PASSWORD_FILE=/path/to/your/password_file) restic init

When restic init runs, it will prompt you to set a new password and then confirm it. If you're using RESTIC_PASSWORD directly, it will use that. If RESTIC_PASSWORD_FILE is set, ensure that file contains only the password on a single line.

A successful initialization will output something like:
```
created restic repository c508c909b9 at /mnt/data/backups/restic
Please go to https://restic.readthedocs.io/en/latest/040_backup.html to learn how to backup your files!
```
Verify the new repository: After initialization, re-run ls -la /mnt/data/backups/restic. You should now see the config file and the repository's directory structure.
Update your restic-backups-nas.service configuration: Now that the repository exists, you need to make sure your restic-backups-nas.service knows where it is and how to access it. This means ensuring RESTIC_REPOSITORY and RESTIC_PASSWORD (or RESTIC_PASSWORD_FILE) are correctly set within your systemd service unit. For NixOS users, this usually involves updating your configuration.nix file under your service definition, something like:
```
systemd.services.restic-backups-nas = {
  description = "Restic NAS Backup Service";
  environment = {
    RESTIC_REPOSITORY = "/mnt/data/backups/restic";
    RESTIC_PASSWORD_FILE = "/path/to/your/restic-password-file";
    # ... other environment variables
  };
  # ... other service options
};
```
Then, rebuild and switch your NixOS configuration: sudo nixos-rebuild switch.

Once the repository is initialized and your restic-backups-nas.service configuration is updated to correctly point to it with the necessary credentials, reload systemd and try starting the service again: sudo systemctl daemon-reload sudo systemctl start restic-backups-nas.service systemctl status restic-backups-nas.service

Hopefully, this time, your Restic NAS backup will kick off without a hitch, and that Fatal: repository does not exist error will be a thing of the past. Remember, the config file is the heart of your Restic repository, and restic init is how you give it that heart!

Verifying Mount Points and Paths for Stable Restic Backups

Alright, team, we've talked about checking for the repository and even initializing it if it was missing. But what if the repository is there, but your restic-backups-nas.service still throws the "repository does not exist" error? This often boils down to an issue with mount points and paths. For any NAS backup system, especially one relying on Restic to securely store data, ensuring that the target storage is consistently available at the correct location is absolutely non-negotiable. If /mnt/data/backups/restic isn't accessible exactly as Restic expects, then your restic-backups-nas.service will inevitably fail, leading to wasted time and potentially lost backups. Let's make sure our storage is always where it should be.

The problem could stem from a few common scenarios:

The underlying physical or network storage isn't mounted.
It's mounted, but at the wrong location.
It's mounted, but temporarily unavailable or unmounted just before the service runs.

Let's walk through how to systematically verify these mount points and paths to ensure the stability of your Restic NAS backup.

First, manually check the path directly from your terminal as the root user or the user running the restic-backups-nas.service. sudo -u your_service_user ls -la /mnt/data/backups/restic (Replace your_service_user with the actual user if it's not root). If this command fails with "No such file or directory" even though you know you've created or initialized the repository, then it's almost certainly a mount issue.

Deep Dive into Mount Status: Use the mount command to list all currently mounted file systems: mount Look for /mnt/data (or whatever the parent directory of your Restic repo is) in the output. Example of a healthy mount: NFS_SERVER:/export/data on /mnt/data type nfs4 (rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.1.100,local_lock=none,addr=NFS_SERVER_IP) If /mnt/data isn't listed, or if it's listed with errors or an incorrect type, then your storage isn't properly attached.

Fixing Persistent Mount Issues: If your mount point isn't consistently coming up, especially after a reboot, you need to configure it to mount automatically at system startup. This is typically done in /etc/fstab for local disks or NFS/CIFS shares, or through systemd.mount units in NixOS.

For /etc/fstab (common on many Linux distros, and often configured by NixOS implicitly): Open /etc/fstab with sudo nano /etc/fstab and look for an entry for /mnt/data. A common entry for an NFS share might look like this: NFS_SERVER:/export/data /mnt/data nfs defaults,noauto,x-systemd.automount,x-systemd.device-timeout=60,_netdev 0 0 Or for a local drive: /dev/sdb1 /mnt/data ext4 defaults 0 2

Crucial Options for Reliability:

_netdev: Essential for network mounts; tells systemd to wait until the network is up.
noauto,x-systemd.automount: This pair tells systemd to not mount it at boot but automatically mount it on first access. This is super useful because it means your system can boot even if the NAS is temporarily down, and restic-backups-nas.service will trigger the mount when it tries to access /mnt/data/backups/restic.
x-systemd.device-timeout=60s: Gives systemd a grace period (e.g., 60 seconds) to wait for the device or network share to become available before giving up.
nofail: (Use with caution) If the mount fails, the system will still boot. This can prevent boot failures but might hide the underlying problem.

NixOS Specific Configuration for Mounts: In NixOS, you'd typically define your mounts in configuration.nix. For example, for an NFS share:

fileSystems."/mnt/data" = {
  device = "NFS_SERVER:/export/data";
  fsType = "nfs";
  options = [ "defaults" "_netdev" "x-systemd.automount" "x-systemd.device-timeout=60s" ];
  # make sure the directory exists
  neededFor = [ "systemd.services.restic-backups-nas.target" ]; # Ensure restic service depends on this mount
};

The neededFor = [ "systemd.services.restic-backups-nas.target" ]; line is incredibly powerful for NixOS users. It tells systemd that your restic-backups-nas.service requires this mount point to be ready before it even tries to start. This explicit dependency helps prevent the "repository does not exist" error due to an unmounted drive.

After modifying /etc/fstab or configuration.nix, remember to apply changes:

For /etc/fstab: sudo systemctl daemon-reload and then sudo mount -a to test if they mount correctly.
For NixOS: sudo nixos-rebuild switch.

By meticulously verifying and correctly configuring your mount points and paths, you significantly boost the reliability of your Restic NAS backup system, ensuring that the restic-backups-nas.service always finds its target repository exactly where it expects it to be, making that frustrating "repository does not exist" error a thing of the past. It's all about robust infrastructure, guys!

Permissions, Permissions, Permissions: The Hidden Culprit for Restic Failures

Alright, let's talk about something often overlooked but critically important when troubleshooting your restic-backups-nas.service: permissions, permissions, permissions! Even if your Restic repository exists at /mnt/data/backups/restic and your mount points are perfectly configured, improper file system permissions can still lead to the dreaded "repository does not exist" error or other access denied messages. Restic, like any good application, needs specific rights to read and write to its designated directory. If the user or group running your restic-backups-nas.service doesn't have these rights, then guess what? It simply can't open that crucial config file, making it appear as if the repository doesn't exist to the service. This is a super common hiccup, especially in multi-user or tightly secured environments like a NAS.

Let's break down how to properly check and set permissions to ensure your Restic NAS backup operates smoothly.

First, identify which user your restic-backups-nas.service is running as. You can usually find this in your systemd service unit file (e.g., /etc/systemd/system/restic-backups-nas.service) under the User= and Group= directives. If these are not explicitly set, the service usually defaults to root. However, it's best practice to run backup services as a dedicated, unprivileged user for security reasons. Let's assume for now your service runs as a user called resticuser.

Now, let's check the permissions on your repository directory: ls -ld /mnt/data/backups/restic You should see output similar to this: -rw-r--r-- 1 resticuser resticgroup 4096 Nov 16 02:50 /mnt/data/backups/restic (This example shows a file, but for a directory, it would start with d instead of -.) The important bits here are the owner (resticuser) and the group (resticgroup), and the permission flags (rwx for read, write, execute).

For Restic to function correctly, the user running the restic-backups-nas.service needs read, write, and execute permissions on the repository directory itself, and also recursively on all its contents.

How to Correct Permissions:

Change Ownership (if necessary): If the owner/group doesn't match the user/group your restic-backups-nas.service runs as, you need to change it. sudo chown -R resticuser:resticgroup /mnt/data/backups/restic The -R flag is crucial as it applies the changes recursively to all files and subdirectories within the repository. Without it, Restic might be able to access the main directory but fail on its contents.
Set Appropriate Permissions: Once ownership is correct, ensure the permissions allow the owner to read, write, and execute. sudo chmod -R u+rwx /mnt/data/backups/restic This command grants the owner user (e.g., resticuser) full read, write, and execute permissions. You might also want to grant read and execute permissions to the group or others if multiple users need to interact with the repository (though for a dedicated backup service, limiting access is often better). A common, relatively secure permission set for directories is 700 (owner has full access, no one else), or 750 (owner full, group read/execute). For the repository directory itself, chmod 700 /mnt/data/backups/restic is usually a safe bet. For files within the repository, chmod 600 is typical. Restic usually manages these file permissions itself during operations, so focusing on the top-level directory's ownership and its initial permissions is key.

Considerations for Network Shares (NFS/CIFS): If your Restic repository is on a network share, permissions can get a bit trickier.

NFS: NFS typically maps UIDs/GIDs. Ensure the resticuser's UID/GID on your storage host matches the UID/GID that has permissions on the NFS server. Sometimes no_root_squash or all_squash options on the NFS server export configuration can influence this.
CIFS/Samba: You might need to specify uid and gid options directly in your fstab entry or systemd.mount unit to map the network share's permissions to a local user: //NAS_IP/share /mnt/data cifs credentials=/etc/samba/credentials,uid=resticuser,gid=resticgroup 0 0 Without these, the mount might default to root or nobody which won't work for your dedicated resticuser.

After adjusting permissions and ownership, reload systemd and restart your restic-backups-nas.service to see if the changes took effect: sudo systemctl daemon-reload sudo systemctl restart restic-backups-nas.service systemctl status restic-backups-nas.service

By meticulously checking and correcting file system permissions and ownership, you eliminate a major potential roadblock for your restic-backups-nas.service. This ensures that Restic has the necessary access rights to open its config file and operate on the repository, making your Restic NAS backup system robust and reliable. Don't let a simple permission error derail your data protection efforts, guys!

NixOS Specific Considerations for Restic Backups

Alright, all you awesome NixOS users out there! This section is specifically for you, because while the core Restic issues like "repository does not exist" and restic-backups-nas.service failures are universal, the way we manage and troubleshoot services on NixOS has its own unique quirks and advantages. When you see nixos mentioned in the discussion category, it immediately signals that we need to think about declarative configurations and the Nix store. So, let's dive into how NixOS handles our Restic NAS backup setup and what unique aspects we need to consider to debug and prevent these restic service failures.

The beauty (and sometimes initial challenge) of NixOS is its declarative nature. Services, users, mounts, and software are all defined in configuration.nix (or linked modules). This means if something isn't working, the first place to look isn't directly at /etc/systemd/system/restic-backups-nas.service (which is symlinked from the Nix store), but at your NixOS configuration files.

Understanding the Nix Store and Restic Paths: Notice the ExecStart line in your service failure report: ExecStart=/nix/store/v0nssfmagban50qs1f4yxd968rd8fhs3-restic-0.18.0/bin/restic backup ... This clearly shows Restic being called from the Nix store. This is standard NixOS behavior. What's important is how you're defining the Restic repository path and credentials within your NixOS configuration.

Declarative Service Definition: Your restic-backups-nas.service is almost certainly defined in your configuration.nix (or a related module like services.restic.backups). This is where you set the RESTIC_REPOSITORY and RESTIC_PASSWORD_FILE environment variables. Make sure your definition is something like this:

# services.restic.backups.<name> in NixOS options
services.restic.backups.nas = {
  enable = true;
  repository = "/mnt/data/backups/restic"; # This sets RESTIC_REPOSITORY
  passwordFile = "/path/to/your/restic-password-file"; # This sets RESTIC_PASSWORD_FILE
  paths = [ "/home/youruser/data" ]; # Paths to backup
  extraBackupArgs = [ "--exclude-file=/nix/store/xz2b3ah77lqpxdci872hngpf8irzsvl3-exclude-patterns" ]; # For your exclude file
  timerConfig = {
    OnCalendar = "daily";
    Persistent = true;
  };
  # If you're managing the service more manually, you might use:
  # systemd.services.restic-backups-nas = {
  #   description = "Restic NAS Backup Service";
  #   environment = {
  #     RESTIC_REPOSITORY = "/mnt/data/backups/restic";
  #     RESTIC_PASSWORD_FILE = "/path/to/your/restic-password-file";
  #   };
  #   # ... other service configurations
  #   # Ensure this service requires the mount point
  #   requires = [ "mnt-data.mount" ]; # If you defined /mnt/data as a systemd.mount
  #   after = [ "mnt-data.mount" ];
  # };
};

Key Takeaway: Verify these paths and variables in your NixOS config. If repository is wrong, or passwordFile is pointing to a non-existent or inaccessible file, your restic-backups-nas.service will fail. The error repository does not exist could simply mean Restic can't access its password file to decrypt the repository info.

Mount Points as systemd.mount Units: As discussed in the previous section, mounts on NixOS are also declarative. If your /mnt/data (or the parent directory of your Restic repo) is a network share or a separate drive, ensure its systemd.mount unit is properly defined and explicitly required by your Restic service. Example:
```
fileSystems."/mnt/data" = {
  device = "NFS_SERVER:/export/data";
  fsType = "nfs";
  options = [ "defaults" "_netdev" "x-systemd.automount" ];
  # Crucial: Ensure the restic service depends on this mount
  # This option creates a dependency that the mount unit is active before this service
  requiredBy = [ "systemd.services.restic-backups-nas.service" ];
};
```
Or, if you used requires = [ "mnt-data.mount" ]; in the service definition, that also works. The point is to make systemd aware of the dependency, preventing the restic-backups-nas.service from attempting to run before the repository location is ready.
nixos-rebuild switch is Your Best Friend: Every time you change your configuration.nix (or any module it imports), you must run sudo nixos-rebuild switch. This command generates the new system configuration, including updated systemd unit files, and activates it. If you manually tweaked a systemd service file in /etc/systemd/system on a NixOS system, those changes are transient and will be overwritten on the next rebuild. Always make changes in configuration.nix.
Logging and Debugging on NixOS: NixOS uses journald extensively. To get detailed logs for your restic-backups-nas.service, you'd use: journalctl -u restic-backups-nas.service -f This provides real-time logs and is invaluable for debugging. Combine this with temporary verbose flags in your Restic command for even more output if you're really stuck.

By understanding how NixOS manages its services and dependencies declaratively, and by meticulously checking your configuration.nix for correct paths, environment variables, and mount point dependencies, you can effectively diagnose and fix restic-backups-nas.service issues like the "repository does not exist" error. This approach not only solves the immediate problem but also ensures a robust and reproducible Restic NAS backup system, which is what NixOS is all about, right? Keep those configs clean, guys!

Debugging Like a Pro: Advanced Tips for Restic Service Failures

Alright, fellow troubleshooters, if you've gone through all the basic checks – verifying mount points, ensuring permissions are spotless, initializing the repository, and even diving into your NixOS configuration – and your restic-backups-nas.service is still stubbornly failing with the "repository does not exist" error, it's time to pull out the big guns and debug like a pro. This isn't just about throwing commands at the problem; it's about systematically isolating the issue and understanding exactly why Restic can't find its repository. Our goal here is to get your Restic NAS backup working flawlessly, even when it feels like the system is fighting back!

1. Manual Execution and Environment Replication

The restic-backups-nas.service is running a specific command with specific environment variables. Replicate this exact environment in your terminal to see if you can trigger the error manually.

Identify the ExecStart command: From your service status, it's: /nix/store/v0nssfmagban50qs1f4yxd968rd8fhs3-restic-0.18.0/bin/restic backup --exclude-file=/nix/store/xz2b3ah77lqpxdci872hngpf8irzsvl3-exclude-patterns --files-from=/run/restic-backups-nas/includes
Identify Environment Variables: Look at your systemd service unit (or configuration.nix for NixOS). You must define RESTIC_REPOSITORY and RESTIC_PASSWORD (or RESTIC_PASSWORD_FILE). Let's assume: export RESTIC_REPOSITORY="/mnt/data/backups/restic" export RESTIC_PASSWORD_FILE="/path/to/your/restic-password-file" (or export RESTIC_PASSWORD="your_actual_password")
Execute Manually as the Service User: sudo -u your_service_user bash (Replace your_service_user with the user the service runs as, e.g., root, restic, etc.) Once inside that user's shell: export RESTIC_REPOSITORY="/mnt/data/backups/restic" export RESTIC_PASSWORD_FILE="/path/to/your/restic-password-file" /nix/store/v0nssfmagban50qs1f4yxd968rd8fhs3-restic-0.18.0/bin/restic backup --exclude-file=/nix/store/xz2b3ah77lqpxdci872hngpf8irzsvl3-exclude-patterns --files-from=/run/restic-backups-nas/includes What happens? Does it work? Does it give a different error? This direct execution is often the quickest way to pinpoint if the issue is with the Restic command itself, the environment variables, or something specific to how systemd executes it. If it works manually, the problem is likely in the systemd service definition (e.g., environment variables not being passed correctly). If it still fails, the problem is more fundamental to Restic's interaction with the repository.

2. Verbose Restic Output

Restic can be quite chatty if you ask it nicely. Add a -v or --verbose flag to your restic command (or even -vv for more verbosity). Modify your ExecStart (or NixOS config) temporarily: ExecStart=/nix/store/v0nssfmagban50qs1f4yxd968rd8fhs3-restic-0.18.0/bin/restic -v backup ... Then sudo systemctl daemon-reload && sudo systemctl restart restic-backups-nas.service and check journalctl -u restic-backups-nas.service -f. The verbose output might give you clues like "trying to open repo at X", "failed to read file Y", which can be incredibly helpful for resolving the restic-backups-nas.service failure.

3. Check for SELinux/AppArmor

On some hardened systems, SELinux or AppArmor might be preventing Restic from accessing /mnt/data/backups/restic even if standard Unix permissions are fine.

SELinux: Check audit logs: sudo ausearch -c 'restic' -m AVC,USER_AVC -ts recent or sudo setroubleshoot. You might see denied messages. If this is the case, you'll need to create a specific SELinux policy.
AppArmor: Check dmesg | grep -i apparmor or sudo aa-status. If AppArmor is active and restricting Restic, you'll need to adjust its profile. While less common on a default NixOS setup unless explicitly configured, it's a possibility on other Linux distributions that might be influencing your Restic NAS backup.

4. Temporary Repository for Testing

If you suspect the restic binary or its interaction with your NAS storage is the issue, try initializing and backing up to a temporary local repository (e.g., /tmp/test-restic-repo) using the exact same Restic binary and command-line arguments (minus the repository path, of course). export RESTIC_REPOSITORY="/tmp/test-restic-repo" export RESTIC_PASSWORD="test" restic init restic backup /path/to/some/small/file If this works, it strongly points to an issue with your NAS mount point or its permissions specifically for /mnt/data/backups/restic. If it fails, then the Restic setup itself (the binary, environment variables, or even a corrupted Nix store path) could be the problem. This helps isolate the restic-backups-nas.service problem immensely.

5. Time Synchronization Issues

While less likely for a "repository does not exist" error, time synchronization (NTP) can cause weird issues with network file systems or backup solutions that rely on accurate timestamps for deduplication or integrity checks. Ensure your storage host's time is correct. timedatectl can show you this.

By following these advanced debugging steps, you'll transform from a casual user into a troubleshooting ninja, equipped to conquer any restic-backups-nas.service failure and ensure your Restic NAS backup system is as rock-solid as your data deserves! Never give up, guys; every error has a solution!

Preventive Measures and Best Practices for Reliable Restic Backups

Alright, folks, we've walked through the painful process of debugging and fixing the dreaded "repository does not exist" error plaguing your restic-backups-nas.service. But hey, an ounce of prevention is worth a pound of cure, right? To save ourselves future headaches and ensure our Restic NAS backup system is as reliable as a Swiss watch, let's talk about some solid preventive measures and best practices. This isn't just about avoiding a restic-backups-nas.service failure; it's about building a robust, set-it-and-forget-it data protection strategy.

1. Automate Repository Initialization (with caution!)

While restic init should generally be a manual, one-time step, you can build checks into your systemd service's ExecStartPre to see if the repository exists. If it doesn't, you could theoretically run restic init. However, this is risky! If your repository gets corrupted and looks "empty," an automated init could wipe out your backups. A safer approach for new setups might be:

Have a pre-start script that checks for the config file.
If config is missing, log a critical warning and exit, perhaps even sending a notification. Do not automatically init unless you have an extremely robust method to differentiate a truly new repository from a corrupted one.
For NixOS, this would involve crafting a custom ExecStartPre script in your service definition that uses a conditional restic init if the repository isn't found, but again, with extreme care. A simple if ! restic check --quiet; then restic init; fi is still dangerous if the repository exists but is corrupt.

2. Regular Repository Checks

Restic has a fantastic command called restic check. This command verifies the integrity of your repository.

Schedule a weekly/monthly restic check: Create a separate systemd timer and service specifically for restic check. This service should run less frequently than your backups but regularly.
```
# Example for NixOS
services.restic.backups.nas-check = {
  enable = true;
  repository = "/mnt/data/backups/restic";
  passwordFile = "/path/to/your/restic-password-file";
  check = true; # Tells NixOS Restic module to run check
  timerConfig = {
    OnCalendar = "weekly";
    Persistent = true;
  };
};
```
If restic check ever reports errors, it's a huge red flag that something is wrong with your Restic NAS backup integrity, and you need to investigate immediately.

3. Implement Robust Mount Management

As we covered, mount points are often the root cause of "repository does not exist."

_netdev and x-systemd.automount: Always use these options for network shares in /etc/fstab or your NixOS fileSystems configuration. This makes your system more resilient to network glitches and ensures the mount is handled gracefully by systemd.
Dependencies in systemd: Explicitly define requires and after dependencies in your restic-backups-nas.service unit file (or requiredBy in NixOS fileSystems) to ensure the mount point is ready before Restic tries to run.

4. Dedicated Backup User and Permissions

Least Privilege Principle: Always run your restic-backups-nas.service as a dedicated, non-root user with the minimum necessary permissions. This limits the potential damage if the service is ever compromised.
Correct Ownership and Permissions: Consistently apply chown and chmod (e.g., chmod 700) to your repository directory /mnt/data/backups/restic and its contents, ensuring the dedicated backup user is the owner and has exclusive read/write/execute access.

5. Securely Manage Restic Password

Password File: Never hardcode your Restic password directly in the service file. Use RESTIC_PASSWORD_FILE and keep this file (/path/to/your/restic-password-file) secure (e.g., chmod 400 and owned by the backup user).
External Storage for Password: For maximum security, consider tools like pass or age for storing the password, especially if your NixOS config is public or in version control.

6. Monitoring and Alerting

Email Notifications: Configure systemd to send email notifications OnFailure of your restic-backups-nas.service. This way, you're immediately alerted if your Restic NAS backup fails again.
```
[Unit]
OnFailure=failure-alert@%n.service
```
You'd then define a failure-alert@.service that sends an email.
Healthchecks.io or UptimeRobot: For external monitoring, use a service like Healthchecks.io. Have your restic-backups-nas.service (or a post-backup script) ping a URL on success. If the ping isn't received, you get an alert.

By implementing these preventive measures and best practices, you're not just reacting to problems; you're proactively building a resilient Restic NAS backup system. This holistic approach ensures that your restic-backups-nas.service runs smoothly, your data is continuously protected, and you can sleep soundly knowing your digital assets are safe. Stay diligent, guys, and happy backing up!