How to Safely Expand a Synology SHR Storage Pool Without Losing Data (2025)

YOUSSEF MOSSTAKIM
How to Safely Expand a Synology SHR Storage Pool Without Losing Data (2025)
How to Safely Expand a Synology SHR Storage Pool Without Losing Data (2025)

How to Safely Expand a Synology SHR Storage Pool Without Losing Data (2025)

One of the best features of a Synology NAS is its powerful and flexible Synology Hybrid RAID (SHR), which allows you to easily manage and expand your storage over time. But the process of actually expanding a storage pool by replacing your existing drives with larger ones can be a nerve-wracking experience. The fear of making a mistake and losing years of precious data is very real. This guide will provide a safe, methodical, and step-by-step process for expanding your Synology SHR storage pool with larger disks, ensuring that your data remains completely safe throughout the entire process.

First, Understanding Synology Hybrid RAID (SHR)

Before you begin, it's important to understand what SHR is. Unlike traditional RAID levels, SHR is an automated RAID management system that optimizes storage volume size when you're using disks of varying capacities. The key feature for this guide is its flexibility. With SHR, you can replace your drives one by one with larger ones, and once all drives have been replaced, you can expand the volume to take advantage of the new, larger capacity.

Phase 1: The Critical Pre-Flight Checklist

Do not skip this phase. Proper preparation is the key to a stress-free and safe expansion.

  1. 1. Verify Your Backup: This is the most important rule. Before you touch a single drive, ensure you have a complete, recent, and verified backup of all critical data on your Synology NAS. Use tools like Hyper Backup to back up to an external USB drive or a cloud service. Test the backup to make sure you can actually restore a file from it. This is your ultimate safety net.
  2. 2. Check Your Storage Pool Health: Open the Storage Manager in your DiskStation Manager (DSM) interface. Go to the "Storage Pool" section and ensure that its status is "Healthy." If the pool is degraded or shows any errors, you must resolve those issues *before* attempting an expansion.
  3. 3. Perform a Data Scrubbing: A data scrub is an integrity check that inspects your volume for any data inconsistencies. It's highly recommended to run a full data scrubbing before you start replacing drives. This can take many hours, so plan accordingly. You can start it from Storage Manager > Storage Pool > Global Settings > Data Scrubbing Schedule.
  4. 4. Check Your New Drives: Make sure your new, larger hard drives are on Synology's official compatibility list for your specific NAS model.

Phase 2: The One-by-One Drive Replacement

The core of the process is to replace your old drives with new, larger ones, one at a time, allowing the RAID to rebuild after each replacement. This process is long and requires patience.

  1. Identify the First Drive: In Storage Manager, go to the HDD/SSD section to see all your drives. Choose the first drive you want to replace.
  2. Deactivate the Drive: Select the drive, click on "Action," and choose "Deactivate." This will safely prepare the drive for removal. Your Synology will start beeping loudly to warn you that the pool is now in a "degraded" state. You can silence the beep from the Control Panel.
  3. Physically Replace the Drive: Power down your NAS (optional but recommended for safety) or use the hot-swap bay to remove the deactivated drive. Insert your new, larger drive into the same slot.
  4. Repair the Storage Pool: Power your NAS back on. Go to Storage Manager > Storage Pool. It will show a "Degraded" status. Select the pool, click the "..." action menu, and choose "Repair." Select the new, larger drive you just added to begin the repair process.
  5. WAIT. This is the Hard Part: The RAID repair and rebuild process can take a very long time—often 24 hours or more, depending on the size of your drives. Your data is still accessible during this time, but performance will be reduced. Do not, under any circumstances, turn off the NAS or remove another drive during this process. You can monitor the progress in the Storage Manager.
  6. Repeat for All Other Drives: Once the storage pool is "Healthy" again, you must repeat steps 2 through 5 for every other drive you intend to replace in the pool.

Phase 3: Expanding the Volume to Use the New Space

After you have replaced all the desired drives with larger ones and the pool is confirmed as "Healthy," you will notice that the storage capacity has not yet increased. There is one final step.

  1. In Storage Manager, go to the Storage Pool you have just upgraded.
  2. Click the "..." action menu and you should now see an option to "Expand."
  3. Follow the expansion wizard, which will allow you to allocate the newly available space. This process is much faster than the RAID repair.

Once the expansion is complete, your Synology NAS will have its new, larger capacity, with all of your original data safe and intact.

Conclusion: A Safe Path to More Storage

Expanding an SHR storage pool is a powerful feature, but it demands a careful and patient approach. By following a strict pre-flight checklist—especially verifying your backup—and methodically replacing and repairing one drive at a time, you can safely upgrade your Synology NAS to meet your growing storage needs without risking a single byte of your precious data.