How much is too much?

Support
1

Ok.

I’m dying here. I have a pair of UnRaid - Uleashed that I use for a Home Server and a onsite mirror.

My data foot print is huge. 30TB and well over a million different files. The initial scan / index of the primary server took about 6 weeks. The mirror’s scan / index was about 90% done. Then the mirror’s instance of Syncthing stopped working. Logs showed a malformed database and the internet said to let it rebuild the database.

So, I did that. I then went to the primary, stopped Syncthing and made a backup of the Syncthing folder.

Started everything back up and all appeared to be well.

Today, I checked Syncthing on my primary and had the malformed database error in the logs on that device. I stopped Synchthing, changed the old folder name and copied the backup folder back into place. No bueno.

Looking at the logs, shows the same pair of errors every second.

2026-06-15 17:50:42 INF syncthing v2.1.1 “Hafnium Hornet” (go1.25.10 linux-amd64) root@buildkitsandbox 2026-06-02 14:11:00 UTC [modernc-sqlite, noupgrade] (log.pkg=main) 2026-06-15 17:50:42 ERR Error opening database (error=“openbase (PRAGMA optimize = 0x10002): database disk image is malformed (11)” log.pkg=main)

Now, I could obviously clear the database and restart the index / scanning process on the main server as I did on the mirror.

But… Having to rebuild the index database frequently is suboptimal and while it is reindexing over the next month and a half, there is some level of vulnerability.

Am I asking too much of Syncthing? Is there a better tool to handle a mirroring and maintenance of that mirror?

2

Not sure it’s the root cause, but it won’t help - you’re using a build that uses the much-less-tested and lower-performance Go port of SQLite. You really want to use a better build, e.g. one of ours.

You might also benefit from the new (in 2.1) option to disable block indexing, since that’ll give you a smaller database with faster inserts on scanning.

3

Ok. Thanks for the insight.

I’m an UnRaid noob, having just jumped over from TrueNAS Scale for the house servers. So (in advance) please forgive my ignorance.

The version I’m using is the Syncthing that is available through the UnRaid App Center. Where would I get a better version? I also see a “binhex-syncthing” in the app center. Should I switch to that build?

Thank you in advance for all the guidance you can provide.