SnapRAID sync stuck at 2% after 34+ hour run? Restarted and it's doing it all over again

[Flavio Lanteri]

Hi everyone,

I'm new to SnapRAID (first time using it) and not a huge expert, so I could really use some advice. I just ran my first snapraid sync on a setup with 70TB of data across nine disks. It took over 34 hours to complete, which seemed reasonable given the size.

After it finished with Everythings OK message, I checked snapraid status and it showed a sync still in progress at only 2%. That's weird, right? I ran snapraid sync again, and now it's starting completely from scratch with an ETA of about 36 hours.

Any idea what's going on? Is this normal behavior, or did something go wrong?

Thanks in advance for any insights!

[Leifi Plomeros]

Something definitely went wrong.

I would recommend to press CTRL + C to stop current sync and pay close attention to what happens.

Expected output:
bla bla interrupted bla bla
Saving state to content files bla bla bla
verifying content files bla bla bla
Everything OK

Verify that above happened as expected.

Then run snapraid status to confirm that progress % is around what would be expected for the amount of time it has been running.

run snapraid diff to confirm that, from snapraids perspective, nothing major has changed since the failed sync started.

If everything still looks good, then modify snapraid.conf by removing the hash tag in front of autosave 500 and change the number to 3000, in order to make snapraid stop and save progress every few hours.

run snapraid sync -l logfile.txt so that you can check the log for errors if still not working as expected.

[Flavio Lanteri]

Thank's to reply.

This are the result of your suggest:

^C%, 37340658 MB, 1238 MB/s, 590 stripe/s, CPU 19%, 23:18 ETA
Stopping for interruption at block 17518161
24% completed, 37340680 MB accessed in 10:22

 d1  0% | 
 d2  0% | 
 d3  0% | 
 d4  4% | **
 d5  1% | 
 d6  0% | 
 d7  0% | 
 d8  0% | 
 d9 75% | *********************************************

parity 2% | *
raid 2% | *
hash 11% | *
sched 0% |
misc 0% |
|______________
wait time (total, less is better)

Everything OK
Saving state to /var/snapraid.content...
Saving state to /mnt/disk1/snapraid.content...
Saving state to /mnt/disk2/snapraid.content...
Verifying...
Verified /mnt/disk2/snapraid.content in 0 seconds
Verified /var/snapraid.content in 0 seconds
Verified /mnt/disk1/snapraid.content in 0 seconds
root@srv01:~# snapraid status
Self test...
Loading state from /var/snapraid.content...
WARNING! For 9 disks, it's recommended to use two parity levels.
Using 4788 MiB of memory for the file-system.
SnapRAID status report:

Files Fragmented Excess Wasted Used Free Use Name
Files Fragments GB GB GB
73019 17 422 42.3 17573 6315 73% d1
1441 1 1 - 7265 2708 72% d2
289 0 0 - 7203 2765 72% d3
306 0 0 - 7163 2757 72% d4
369 0 0 - 7233 2687 72% d5
347 0 0 - 7119 2800 71% d6
28899 0 0 - 7143 2776 72% d7
26207 0 0 - 7170 2758 72% d8
15317 0 0 - 4172 1780 70% d9

---

146194 18 423 42.3 72045 27351 72%

91%| o
| o
| o
| o
| o
| o
| o
45%| o
| o
| o
| o
| o
| o
| o o
0%|o____________o_*
50 days ago of the last scrub/sync 0

The oldest block was scrubbed 50 days ago, the median 0, the newest 0.

WARNING! The array is NOT fully synced.
You have a sync in progress at 26%.
27% of the array is not scrubbed.
No file has a zero sub-second timestamp.
No rehash is in progress or needed.
No error detected.
root@srv01:~# snapraid diff
Loading state from /var/snapraid.content...
WARNING! For 9 disks, it's recommended to use two parity levels.
Comparing...
add media/covers/Video/Tre\ ciotole\ (2025)/front.jpg
add media/covers/Video/Tre\ ciotole\ (2025)/back.jpg

146194 equal
2 added
0 removed
0 updated
0 moved
0 copied
0 restored
There are differences!

The differences are two files that I add later.

My snapraid.conf:

Parity location(s)
parity /mnt/parity1/snapraid.parity

Content file location(s)
content /var/snapraid.content
content /mnt/disk1/snapraid.content
content /mnt/disk2/snapraid.content

Data disks
data d1 /mnt/disk1/
data d2 /mnt/disk2/
data d3 /mnt/disk3/
data d4 /mnt/disk4/
data d5 /mnt/disk5/
data d6 /mnt/disk6/
data d7 /mnt/disk7/
data d8 /mnt/disk8/
data d9 /mnt/disk9/

Excludes hidden files and directories
exclude .unrecoverable
exclude /tmp/
exclude /lost+found/
exclude downloads/
exclude appdata/
exclude .!sync

[Leifi Plomeros]

I can't see anything wrong and sync is doing progress.
So I guess you should simply run sync again to let it finish and then pay extra attention on diff and status for the next few syncs.