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What to Do When Synology Storage Becomes Degraded

Seeing a yellow or red storage warning inside Synology DiskStation Manager can be alarming, especially when the NAS contains business files, backups, virtual machines, or other critical data. A degraded storage pool does not automatically mean your data is lost, but it does mean the storage environment has lost some level of redundancy and requires immediate attention.

Synology categorizes degraded storage as an attention condition, while a crashed storage space represents a more serious danger state. The most important step is to avoid making rushed changes before confirming which drive or component caused the problem.

This guide explains the safest first steps for a Synology degraded storage pool fix, when a normal repair may be appropriate, and when to seek instant Synology support before the situation becomes more serious.

What Does “Degraded” Mean on a Synology NAS?

A degraded storage pool generally means the RAID or SHR configuration has lost redundancy because one of its required drives is unavailable or experiencing a problem.

Depending on the RAID configuration, your NAS may continue operating normally while degraded.

Users may still be able to:

  • Access shared folders

  • Run applications

  • Open files

  • Use Synology Drive

  • Complete backups

However, the remaining drives may now be providing less fault tolerance.

That means a second failure could create a much more serious recovery situation.

Step 1: Do Not Panic or Rebuild Immediately

When DSM displays a degraded storage warning, avoid making several changes at once.

Do not immediately:

  • Remove multiple drives

  • Reinitialize the storage pool

  • Delete the volume

  • Format disks

  • Restart repeatedly

  • Begin experimental RAID recovery

Your first objective is identifying exactly what DSM reports.

Unnecessary changes can complicate troubleshooting and, in serious cases, make later recovery more difficult.

Step 2: Open Storage Manager

Start by opening:

DSM > Storage Manager

Review the storage pool and affected volume.

Synology’s repair guidance specifically recommends checking the degraded storage pool and verifying the drive status before replacing hardware.

Look for information such as:

  • Storage pool status

  • Volume status

  • Drive health

  • Failed or missing drive

  • Available drive slots

  • System notifications

Take screenshots of warnings before making changes.

These records may be valuable if the problem requires escalation.

Step 3: Identify the Correct Drive

One of the most dangerous mistakes during a degraded RAID event is removing the wrong disk.

Check:

Storage Manager > HDD/SSD

Identify:

  • Drive slot

  • Serial number

  • Health status

  • Drive model

  • SMART warnings

Synology’s documented storage pool repair procedure instructs administrators to confirm which drive is defective through Storage Manager before removing it.

Do not rely only on the color of a drive LED.

Confirm the disk in DSM before touching the hardware.

Step 4: Determine Why the Drive Dropped

A degraded pool does not always mean that the drive has completely failed.

Possible causes can include:

  • Drive failure

  • Accidental drive removal

  • Connection problems

  • System partition issues

  • Storage hardware problems

For example, Synology provides a specific recovery procedure for a drive that was accidentally removed from a storage pool. In supported DSM versions, the drive may be reinserted and the degraded pool repaired through Storage Manager.

This is why diagnosis should come before replacement.

Step 5: Check Your Backups

Before starting any RAID repair, verify whether your important data exists somewhere else.

Check:

  • Hyper Backup

  • Snapshot Replication

  • Another Synology NAS

  • Synology C2

  • Active Backup repositories

  • External backup media

  • Other offsite copies

If the storage pool contains irreplaceable business information and no verified backup exists, consider getting professional assistance before performing major changes.

Step 6: Check the Remaining Drives

A degraded RAID rebuild places sustained load on surviving drives.

Before beginning repair, review the health of every remaining disk.

Look for:

  • SMART warnings

  • Bad sector growth

  • I/O errors

  • Abnormal drive health

  • Previous failure notifications

If several drives show warning signs, simply replacing one disk and starting a rebuild may introduce additional risk.

This is an important point where instant Synology support can be valuable.

Step 7: Replace the Failed Drive When Appropriate

If the failure has been confirmed and the RAID configuration supports repair, install a compatible replacement drive.

Synology’s documented process is to remove the defective drive, install a healthy replacement, return to the degraded storage pool, select Repair, choose the replacement drive, and follow the repair wizard. If the NAS does not support hot-swapping, Synology advises powering the device off before removing or installing drives.

Remember that data already present on the replacement drive will be erased when it is added to the storage pool.

Step 8: Monitor the RAID Repair

Once the repair begins, monitor it closely.

Check:

  • Repair progress

  • Drive temperatures

  • Storage pool status

  • System notifications

  • Performance

  • Additional disk errors

Large arrays can require substantial time to rebuild.

Avoid unnecessary workload changes while the storage system is under repair.

What If the Volume Says “Crashed”?

A crashed volume is more serious than a degraded storage pool.

Synology distinguishes between an attention state, which can include a degraded storage pool, and a danger state where a storage space has crashed.

If you need Synology volume crashed help, avoid trying random fixes.

You should consider immediate escalation when:

  • The volume no longer mounts

  • Multiple disks disappeared

  • The pool reports crashed

  • Important files are inaccessible

  • Several drives show errors

  • A previous rebuild failed

  • There is no current backup

At this point, preserving the existing array state may be more important than immediately attempting another repair.

What If the System Partition Is Degraded?

DSM can also report a degraded or failed system partition.

Synology provides a separate repair process for this condition. Current guidance directs administrators to open Storage Manager, use the available Repair option, and then inspect any drives that continue showing a System Partition Failed status because those disks may require replacement.

Do not assume a system partition warning and a degraded RAID pool are the same problem.

Common Mistakes to Avoid

During a storage emergency, avoid:

  • Pulling the wrong drive

  • Removing several drives at once

  • Reinitializing the NAS

  • Formatting the volume

  • Rebuilding repeatedly

  • Ignoring warnings on surviving disks

  • Installing an undersized replacement drive

  • Treating RAID as a backup

The safest response depends on the exact storage configuration and failure condition.

When You Need Instant Synology Support

Some degraded storage incidents can be resolved using DSM’s standard repair workflow.

Others need more careful diagnosis.

Seek instant Synology support when:

  • You cannot identify the failed disk

  • Multiple drives show errors

  • RAID repair will not start

  • The volume is crashed

  • The NAS contains irreplaceable information

  • No verified backup exists

  • A rebuild has already failed

  • Business operations are affected

Getting help before making destructive changes can preserve more recovery options. Get expert help for degraded Synology storage warnings.

Preventing Another Degraded Storage Emergency

Once the system returns to a healthy state, review why the failure occurred.

Organizations should implement:

  • Regular drive health monitoring

  • Storage notifications

  • SMART testing

  • Scheduled data scrubbing

  • Independent backups

  • Offsite replication

  • Spare-drive planning

  • Routine recovery testing

A healthy RAID configuration improves availability, but independent backups remain essential for ransomware, deletion, corruption, and site-level disasters.

Why Organizations Choose Synology

Synology provides centralized storage monitoring, RAID and SHR protection, Btrfs, Snapshot Replication, Hyper Backup, Active Backup, and DSM health notifications that help organizations identify storage problems and maintain recoverable business data. Proper configuration, proactive monitoring, and timely support are essential when storage warnings appear.

About Epis Technology

Epis Technology helps organizations diagnose and resolve Synology storage problems through instant Synology support, RAID troubleshooting, storage pool assessment, drive replacement planning, performance optimization, backup architecture, disaster recovery, and ongoing managed support. When a degraded pool, crashed volume, failed backup, or unexpected DSM alert threatens business operations, Epis Technology provides experienced Synology guidance to help organizations determine the safest next step before a recoverable storage problem becomes a larger data-loss incident.

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