Verify sha256 hash


The past couple of days I’ve been getting the following backup warning:

* 2020-02-17 19:53:47 +00 - [Warning-Duplicati.Library.Main.Operation.FilelistProcessor-MissingRemoteHash]: remote file is listed as Uploaded with size 0 but should be 5447629, please verify the sha256 hash "Zo5BVHRu7KMVt7PQCRZY7qXPSxpzPQIY8taTYbDXjFM=" * 2020-02-17 19:53:57 +00 - [Warning-Duplicati.Library.Main.Operation.FilelistProcessor-MissingRemoteHash]: remote file is listed as Uploaded with size 0 but should be 5447629, please verify the sha256 hash "Zo5BVHRu7KMVt7PQCRZY7qXPSxpzPQIY8taTYbDXjFM="

The file is infact 0 bytes when I check the remote SMB backup share.

I’ve tried to delete the dblock file and run purge broken files command but I then got an error about orphaned files, so purge couldn’t run.

Any suggestions? I’m stuck at the moment.


Update - I restored the 0 byte dblock I deleted, then backed up my Database, then ran a “Recreate (Delete and repair)” on the database, once this was done I was able to delete the 0 byte dblock and run purge broken files without the Orphan file message.
Ran the backup again and no errors.

Welcome to the forum @egtrev

Backing up to an SMB destination seems to be a common source of troubles. Sometimes they’re very solid (at least one person moved to NFS for reliability), other times the suspicion is that an intermittent connection (e.g. laptop moving around) contributed. Your file was believed to be uploaded, but wasn’t.

Although zero is a special number, sometimes files are non-zero-short with a round size inhexadecimal. Although this has been observed, I’m not sure if a reproducible case has been available to be looked at (and even if that were the case, the conclusion might be that Duplicati did OK, and SMB dropped data).

Is Duplicati on Windows, Linux, or something else? There might be some client-side tweaks to help this.
Please verify the sha256 hash? helped Linux, and Windows has some options. What’s the destination? Unfortunately I’m not personally familiar with all the tricks to help SMB, but I can see that some exist…

It’s on Windows 10 backing up to a SMB share (on a local Linux NAS).
I believe the issue started when I had my laptop outside of the local network, but temporary connected to my local VPN, so the local Duplicati backup went ahead because the SMB destination was temporary available over the VPN, I’m thinking the connection got lost at some point causing it to not backup correctly. When I ran the list broken files command, the broken files/dates matched when I was not at home. Backup has been solid for a year now and my B2/Google Cloud Duplciati backup was not affected.

The cloud backups are probably more reliable (in a way) because they don’t try to accept data from Duplicati for later delivery. If it fails (which it will if there’s no connectivity), it fails right then and there subject to –number-of-retries before any error. If it finally errors, it should pick up on the next backup.

Anyway, I’m glad you’ve got several backups (good idea) and even SMB seems to not be intolerable.