Raised from Ticket #3516
Overview
This article clarifies how the UniFi Network Video Recorder (UNVR) handles RAID configurations, drive initialization, and hot spare functionality. It combines insights from official UniFi documentation, Crosstalk Solutions’ setup guides, and field experience.
RAID Configuration Options in UNVR
The UniFi UNVR supports several RAID configurations, but the most commonly recommended for security camera setups is RAID 5 due to its balance of redundancy and usable storage.
- RAID 5 requires a minimum of 3 drives
- Provides 1 drive’s worth of redundancy
- Allows for one drive failure without data loss
- Offers better storage efficiency than RAID 1 or RAID 10
For example, 3 x 10TB drives in RAID 5 = 30TB total – 10TB for parity = 20TB usable storage
For example, 4 x 10TB drives in RAID 5 = 40TB total – 10TB for parity = 30TB usable storage
Hot Spare Drive Behavior
What Is a Hot Spare?
A hot spare is a drive that is pre-installed and sits unused until another drive fails. When a failure occurs, the system automatically begins rebuilding the array using the hot spare.
Important Clarifications:
- The hot spare must be installed during the RAID setup phase.
- You cannot insert it later without reinitializing the array.
- Reformatting the array is required to enable the hot spare function.
Hot Spare Use Case:
In a 4-drive RAID 5 setup:
- 3 drives are active
- 1 drive is the hot spare
- For example, 4 x 10TB drives in RAID 5- but one is just a standby, doing nothing = 40TB total – 10TB for parity and -10 for hot spare = 20TB usable storage
- Hot spare and raid 5 would require four drives, so there’s no 3 drive option.
This allows for faster failover and quicker recording recovery, although it still requires some time to rebuild after a failure.
Initialization and Setup Considerations
Initialization Time
Initial drive formatting and RAID setup can take a long time—estimates vary based on drive size and health. For 10tb drives, 2 days is a conservative estimate, though this may shorten significantly once the initialization progresses past early stages.
System Behavior When Drives Are Added or Removed
- UNVR is not a hot-add system. Adding or removing drives resets existing footage.
- Adding a fourth drive after the fact (not during initial setup) means a full reformat is required, and previous recordings will be lost.
- Always backup data before any changes to the RAID array.
Recommended Action Steps
- Initial Setup
- Install all drives (including intended hot spare)
- Choose RAID 5 during setup
- Configure the hot spare at the time of initialization
- If Adding a Hot Spare Later
- Backup any critical data
- Insert the fourth drive
- Reformat the RAID array and enable hot spare role for the new drive
- Post-Setup Maintenance
- Monitor drive health via UniFi Protect
- Replace failed drives promptly
- Ensure that replacement drives match size and speed class for best results
Summary
| Configuration | Drives Used | Usable Storage | Redundancy | Notes |
|---|---|---|---|---|
| RAID 5 Only | 3 x 10TB | 20TB | 1 drive | Good storage-to-redundancy ratio |
| RAID 5 + Hot Spare | 4 x 10TB | 30TB | 1 drive + 1 hot spare | Higher resilience, slower total storage setup |
| Adding Drive Later | N/A | N/A | N/A | Requires full reformat and loss of current footage |
References
- 🔗 UniFi Storage Protection & Data Redundancy Article
- 📺 Crosstalk Solutions: UNVR Setup & RAID (start at Hard Drive/RAID chapter)
- 📺 UNVR Drive Initialization Video Clip
Notes from Support Experience
- Formatting large drives can be slow initially but speeds up as the process progresses.
- Hot spare must be present at setup to be configured easily.
- Rebuilding after failure using a hot spare is faster than traditional full array rebuilds, but not instant.
- Backup capability is limited through UniFi Protect, so plan for external backups if data preservation is critical.
