Troubleshooting Samba Writing To Boot Drive Instead Of ZFS Drive

Aug 24, 2025 by ADMIN 65 views

SMB Writing to ZFS Drive Troubleshooting Guide

Hey guys! Building a homelab can be an awesome adventure, but sometimes you run into snags like the one we're tackling today. It sounds like you've got a solid setup with your RAID1 SSD boot drives and your RAIDZ1 HDDs for storage. But here's the puzzle: your Samba shares seem to be writing to the boot drive instead of the spacious ZFS drive you intended. Don't sweat it, we'll figure this out together! This comprehensive guide will walk you through troubleshooting steps to ensure your Samba shares write to your ZFS drive as expected, and will provide the necessary context to understand the underlying system configurations.

Understanding the Setup

Before we dive into the nitty-gritty, let's make sure we're all on the same page regarding your setup. You've got two 120GB SSDs in a RAID1 configuration, which means they're mirrored for redundancy. This is your boot drive, and it’s where your operating system lives. Then, you've got two 8TB HDDs in a RAIDZ1 configuration, which gives you both storage capacity and some level of redundancy. RAIDZ1 is similar to RAID5, offering single-drive failure protection. The goal here is to have your Samba shares utilize the large storage capacity of your RAIDZ1 array, ensuring that your data is stored safely and efficiently. It's crucial to understand the distinction between the boot drive and the storage drive to avoid filling up your boot drive with data that should be on the ZFS array. A full boot drive can lead to system instability and performance issues, so let's get this sorted out!

Key Components

Boot Drive (RAID1 SSDs): This is where your operating system and essential system files reside. It's important to keep this drive lean and mean, focusing on system-related data rather than user files.
Storage Drive (RAIDZ1 HDDs): This is your bulk storage, perfect for housing your Samba shares, media files, and other data. The RAIDZ1 configuration provides a balance between storage capacity and data protection.
Samba: Samba is the software that allows you to share files and printers between Linux/Unix systems and Windows machines. It's the bridge that lets your homelab interact with other devices on your network.
ZFS: ZFS is a combined file system and logical volume manager designed for high storage capacity, data integrity, and ease of administration. It's a powerful tool for managing your storage drives.

Identifying the Problem

The core issue here is that Samba is writing data to the boot drive instead of the ZFS drive. This usually happens due to misconfiguration in Samba or incorrect mount points. When setting up Samba shares, you need to explicitly tell it where to store the files. If this isn't done correctly, Samba might default to writing to the root file system, which resides on your boot drive. We need to pinpoint exactly where Samba is configured to write files and ensure that it aligns with your intention of using the ZFS drive.

Common Causes

Incorrect Samba Configuration: The Samba configuration file (smb.conf) might have the wrong path specified for the shared directories. This is the most common culprit.
Mount Point Issues: The ZFS drive might not be mounted correctly, or the mount point might not be what Samba expects. We need to verify that the ZFS drive is mounted, accessible, and that Samba is pointing to the correct mount point.
Permissions Problems: Samba might not have the necessary permissions to write to the ZFS drive. File permissions are crucial in Linux-based systems, and if Samba doesn't have the right permissions, it won't be able to write to the intended storage location.
Default Share Settings: Sometimes, default Samba share settings can override your intended configuration. We'll need to check for any conflicting default settings that might be causing the issue.

Troubleshooting Steps

Alright, let's get our hands dirty and start troubleshooting! We'll go through a series of steps to identify and fix the problem. Each step is designed to isolate potential issues and guide you towards a solution.

1. Verify ZFS Mount Points

First things first, we need to ensure that your ZFS drive is properly mounted. This means that the ZFS filesystem is attached to a specific directory in your system, making it accessible. Open your terminal and let's run a couple of commands to check this out.

zfs list

This command will list all ZFS datasets and their mount points. Look for your RAIDZ1 pool and dataset. You should see a mountpoint property indicating where it's mounted. For example:

NAME        USED  AVAIL     REFER  MOUNTPOINT
zpool/data  1.2T  6.7T      1.1T  /mnt/data

Here, zpool/data is the ZFS pool and /mnt/data is the mount point. If you don't see your ZFS pool or the mount point looks incorrect, you'll need to investigate further. A missing or incorrect mount point is a major red flag and needs immediate attention.

Next, let's use the df -h command to verify the mount points in the file system.

df -h

This command displays disk space usage in a human-readable format. Look for your ZFS pool and make sure it's mounted at the expected location. This command provides a comprehensive view of all mounted file systems, including your ZFS pool, which helps in confirming that it is correctly mounted and accessible within the system.

If the ZFS drive isn't mounted, you can try mounting it manually:

zfs mount zpool/data

Replace zpool/data with your actual ZFS pool name. If this command fails, there might be an underlying issue with your ZFS pool, such as import problems or other errors. You'll need to address these ZFS-related issues before proceeding with Samba troubleshooting. Correctly mounting the ZFS drive is a foundational step in ensuring that Samba can access and use the storage as intended.

2. Inspect Samba Configuration (smb.conf)

Now, let's dive into the Samba configuration file, smb.conf. This file is the heart of Samba, where you define your shares, set permissions, and configure various other settings. The most common location for this file is /etc/samba/smb.conf, but it might be in a different location depending on your distribution. Open the file with your favorite text editor using sudo to ensure you have the necessary permissions:

sudo nano /etc/samba/smb.conf

Scroll through the file and look for the share definitions. These sections typically start with [share_name], where share_name is the name you've given to your share. Within each share definition, there are several parameters, but the key one we're interested in is the path parameter. This parameter specifies the directory that the share points to.

For example, you might see something like this:

[my_share]
   comment = My Share
   path = /mnt/data/my_share
   browseable = yes
   writable = yes
   guest ok = no
   read only = no

In this case, the path is /mnt/data/my_share. Make sure that this path points to a location on your ZFS drive, not your boot drive. If the path is incorrect, this is likely the root cause of your problem. Update the path to the correct location on your ZFS drive. For instance, if your ZFS pool is mounted at /mnt/zfs, the path should be something like /mnt/zfs/share_name.

Also, check for any conflicting share definitions or global settings that might be overriding your intended configuration. Sometimes, there might be a default share defined that's inadvertently directing traffic to the boot drive. Ensure that all paths are correctly pointing to your ZFS storage.

After making any changes to smb.conf, you need to restart the Samba service for the changes to take effect. You can do this with the following command:

sudo systemctl restart smbd

This command ensures that Samba reloads its configuration and applies your changes, which is crucial for the fix to work.

3. Check File Permissions

File permissions are a fundamental aspect of Linux-based systems, and they control who can access and modify files and directories. Samba needs the correct permissions to write to the ZFS drive. Let's verify that Samba has the necessary permissions to access the share directories. Navigate to your ZFS mount point and check the permissions of your share directories:

ls -l /mnt/data

Replace /mnt/data with your actual ZFS mount point. The output will show the permissions for each file and directory. You're looking for the permissions of the directory that your Samba share points to.

For example, you might see something like this:

drwxr-xr-x 2 root root 4096 Jun 1 10:00 my_share

The drwxr-xr-x part tells you the permissions. In this case, the directory is owned by root and the group is root. Samba typically runs under the nobody user and the nogroup group, so it needs appropriate permissions to write to this directory.

To grant Samba the necessary permissions, you can use the chown and chmod commands. First, let's change the ownership of the directory to the Samba user (usually nobody):

sudo chown nobody:nogroup /mnt/data/my_share

Replace /mnt/data/my_share with the actual path to your share directory. This command changes the owner and group of the directory to nobody and nogroup, respectively.

Next, let's set the permissions to allow Samba to read and write to the directory:

sudo chmod 775 /mnt/data/my_share

This command sets the permissions to rwxrwxr-x, which means the owner and group have read, write, and execute permissions, and others have read and execute permissions. This should be sufficient for Samba to write to the directory.

Correct file permissions are vital for Samba to function correctly. Without the appropriate permissions, Samba will be unable to write to the ZFS drive, resulting in the issue we're trying to solve.

4. Check Samba User Permissions

In addition to file system permissions, Samba also has its own user management system. You need to ensure that the Samba users have the correct permissions within Samba itself. This involves checking the Samba user database and ensuring that the users have the necessary access rights.

First, let's list the Samba users:

sudo pdbedit -L

This command lists all the Samba users configured on your system. You should see the users that you've added for Samba access. If a user isn't listed, you'll need to add them using the smbpasswd command:

sudo smbpasswd -a username

Replace username with the actual username you want to add. This command will prompt you to set a Samba password for the user. Samba user management is distinct from system user management, so you need to add users specifically to Samba if they need access to the shares.

Next, verify that the users have the correct permissions within the Samba configuration. Go back to your smb.conf file and check the share definitions. Look for parameters like valid users, read only, and writeable. These parameters control which users have access to the share and what level of access they have.

For example:

[my_share]
   comment = My Share
   path = /mnt/data/my_share
   browseable = yes
   writable = yes
   guest ok = no
   read only = no
   valid users = user1, user2

In this example, only user1 and user2 have access to the my_share share. Make sure that the users you want to have access are listed in the valid users parameter, if it's used. If read only = yes, users won't be able to write to the share, so ensure it's set to no if you want write access. Samba user permissions are critical for controlling access to your shares and preventing unauthorized data modification.

5. Test with a Simple File

After making any changes to your configuration, it's crucial to test whether the issue is resolved. A simple way to do this is to try writing a small file to the Samba share from a client machine. This test will quickly verify whether Samba is writing to the correct location and whether permissions are set up correctly.

On your client machine, connect to the Samba share and try creating a new file. For example, you can create a text file and write some text into it. If the file is successfully created and saved to the share, then Samba is writing to the correct location. This is a positive sign that your changes have had the desired effect.

Next, check the file on the server to make sure it landed in the right spot. Navigate to the share directory on your ZFS drive and look for the file you just created. If the file is there, congratulations! You've successfully configured Samba to write to your ZFS drive. If the file isn't there, or if you encounter any errors during the file creation process, then there's still an issue to be resolved. Go back through the previous steps and double-check your configurations and permissions.

If you're still facing issues, try checking the Samba logs. The logs can provide valuable insights into what's going wrong. The Samba logs are typically located in /var/log/samba/. Look for files named log.smbd and log.nmbd. These logs can contain error messages and other information that can help you pinpoint the problem. Analyzing the Samba logs is often the key to unlocking complex issues and identifying the root cause of problems.

Conclusion

Alright, we've walked through a bunch of steps to get your Samba shares writing to your ZFS drive. From verifying mount points to checking Samba configurations and file permissions, we've covered the key areas that can cause this issue. Remember, building a homelab is all about learning and tinkering, so don't get discouraged if things don't work perfectly the first time.

By systematically troubleshooting each component, from ZFS mount points to Samba configurations and permissions, you can effectively diagnose and resolve issues. The key is to take a methodical approach and verify each step to ensure everything is correctly configured. If you're still scratching your head, don't hesitate to dive deeper into the Samba logs or seek help from the community. There are tons of folks out there who have been in your shoes and are happy to lend a hand.

Happy homelabbing, and may your data always land on the right drive!