TerraMaster Forum

F4-425 with three drives: 8 TB, 10TB, and 16TB drives. After creating the Pool, Synchronizing the Pool and Volume is very very slow. I thought it was frozen, so I deleted both at 2% and rebuilt them. They’re again taking a very long time. Maybe 1% or 2% an hour? Originally, I setup a pool with just the single 16TB drive and that was almost immediate.

The smaller drives are white label shucked from external enclosures. Both showed as green-check as normal in TOS.

ShoutingMan wrote: ↑10 Apr 2026, 10:00

We understand your disappointment due to the long wait time. Please allow me to explain: this is not a quality issue, but rather the physical time required for large-capacity RAID verification.

Regarding the "slow synchronization speed" issue, I want to explain the real reason behind it. This is not due to poor device performance, but rather to protect your future data security:

Why is it so slow? — This is not "copying," it's "verification."

The mode you selected (such as RAID 5, RAID 6, TRAID, etc.) is performing a full background verification of the hard drive.

When you create a single disk, no verification is required, so it can be completed immediately.

Key point: For large-capacity hard drives (e.g., 8TB, 16TB), the physical time for a full disk read/write operation is inherently very long (approximately 1-2 hours per TB). This is not a machine crash, but a limitation of the hard drive's physical characteristics. Therefore, your synchronization time of approximately 2 days is normal; don't worry, just wait patiently for the synchronization to complete.

Are you creating an array for the first time? After using multiple hard drives to set up the array, synchronization is a mandatory process. This process will take a long time, and the larger the hard drive capacity, the longer it will take. For a 10TB hard drive, the synchronization is expected to take about 20 hours.

TMroy wrote: ↑10 Apr 2026, 11:50

Is that with or without enabling 'Fast Sync' and 'Faster Raid Repair'?

Ok thanks. It’s about 25% complete after running for about 10 hours, so far.

I’m using TRAID. I’m creating an array for the first time with multiple drives.

I couldn’t find anything about this in the TOS6 documentation or the forums with a couple of quick searches. I was concerned my TM NAS might be broken.

About 50% after about 24 hours, so should be done tomorrow night. do feeling better about this. Hasn’t frozen like it did the first time. Then can do the app install and data copy.

ShoutingMan wrote: ↑11 Apr 2026, 05:39 About 50% after about 24 hours, so should be done tomorrow night. do feeling better about this. Hasn’t frozen like it did the first time. Then can do the app install and data copy.

Sounds good.
You can open Terminal and enter a command to check the sync speed. If you think the speed is too slow, try running a read test on both white-label drives after the sync is complete.
(Control Panel > Storage Management > Drives > More > Benchmark)

Gremlin wrote: ↑10 Apr 2026, 17:39

TMroy wrote: ↑10 Apr 2026, 11:50

Is that with or without enabling 'Fast Sync' and 'Faster Raid Repair'?

"Faster Raid Repair" is only applicable when synchronizing an array by skipping identical data blocks and syncing only the differing portions, thereby achieving faster array synchronization. This feature does not apply to newly created arrays.