Move WEBDAV sync store from NAS to another NAS

Tomorrow I will receive my brand new NAS. My idea is simply move disks from one to the another, but Synology says that it is not recommenced from the specific original NAS to the destination NAS does not matter if they are from same manufacturer.

I have a full backup of the NAS across clouds and accounts, all except the DT sync database. Now I’m coping the sync database to my local iMAC via SFTP…

My question is if I restore the local copy over the new created NAS disks, same names, same all except the data has been FTPed… What chances are it won’t work?

After some thinking, I answer to myself: even in the case it could be done, only one device touching the export db while I’m copying it (and it is BIG: 1.1 TB, so it is very probable it will be “touched”) will invalidate the copied version.

Then, what I’m going to do in case moving disks didn’t worked (most probable as Synology says), I will recreate it from my “server” DT installation once I’ve installed the new NAS.

Starting from scratch is often a much better method than trying to shortcut a process. If there is little overhead involved, tests can be made. But when you’re talking about a large amount of overhead, getting a baseline start is a better idea.

Moved disks to new NAS, switched on, recognized disks and started working without trouble… but… new NAS allowed install Virtual Machines… but… my current NAS file system was EXT4 and for VM need to be BTRFS… Long story short, I reinstalled all from scratch (still downloading from cloud security copy)…

But that is not what I wanted to say. Before updating, my sync database was 1.1 TB. Now is 330 GB, that is near my content. I know when I add (or reinstall) a new iOS device, mostly Inbox (as it the place where all the stuff go in first place), “plays” the entire history of inboxed items, adding and then deleting stuff until it is synced. And then it deletes some thousands of files before finish synced.

I understand that is the “secure” way to not to lose things, but, apart to regenerate a new sync store, is there any way to minimize the used sync store or at least periodically “compact” it? For local storage that can be done from Tools menu, but ignore how (and if) it can be done in the sync debase as well.


It’s not clear what you’re asking here, but no you can’t compact a database or sync store.

Yes, that was my question.

And is fine with me not able to reduce its size.


I also moved from an old NAS to a new NAS this week. I initially had the same questions as rfog as my new NAS also supports BTRFS, which seems to be better than EXT4 due to it’s data-checksum ability. Data-checksum addresses an issue called “bit rot” where single bits of files might switch over time, leading to file corruption. BTRFS is able to detect and self-heal those changed bits which is neat.

I did the migration to the new NAS via Synology’s standard backup software (Hyper Backup) which worked pretty well: it copied all the folders from the backup onto the new NAS within a day. I then started my NAS services like WebDav, which I use to sync my DevonThink clients. All were able to connect and sync without any issues. Great!

Recently I noticed, that the above neat data-checksum (and self-healing) ability is not turned on by default. It must be enabled for each shared folder separately. New shared folders seem to get the flag by default, but all my migrated folders have data-checksum turned off. Synology recommends leaving it off in case the share folder is used for databases, virtual machines or recordings of surveillance stations.

I was wondering if my DevonThink shared folder should be considered a database or not. Or - to be more specific - if there are some known issues turning on the data-checksum ability on synced folders on a BRTFS NAS.

Just to let you know: I turned the data-checksum feature on about four weeks ago and didn’t have any issues. This is what I did:

  • turned off WebDav to disable sync
  • renamed the shared folder I use for DEVONthink into something else
  • created a new shared folder for DEVONthink with the original name and data-checksum turned on
  • moved all the files from the old to the new DEVONthink shared folder
  • turned on WebDav
  • synced all my devices