Here are the results of the verbose logging:
2021-11-10 16:54:13 -05 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started
2021-11-10 16:56:35 -05 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
Duplicati.Library.Interface.UserInformationException: Unexpected difference in fileset version 0: 11/2/2021 8:50:14 AM (database id: 1), found 95877 entries, but expected 95878
at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency (System.Int64 blocksize, System.Int64 hashsize, System.Boolean verifyfilelists, System.Data.IDbTransaction transaction) [0x0036e] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Backup.BackupDatabase+<>c__DisplayClass34_0.<VerifyConsistencyAsync>b__0 () [0x00000] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Common.SingleRunner+<>c__DisplayClass3_0.<RunOnMain>b__0 () [0x00000] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Common.SingleRunner.DoRunOnMain[T] (System.Func`1[TResult] method) [0x000b0] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.BackupHandler.RunAsync (System.String[] sources, Duplicati.Library.Utility.IFilter filter, System.Threading.CancellationToken token) [0x0034d] in <1d9349a5d6874088879a75d074c92b62>:0
2021-11-10 16:56:37 -05 - [Information-Duplicati.Library.Modules.Builtin.SendMail-SendMailComplete]: Email sent successfully using server: smtp://smtp.gmail.com:587?starttls=always
2021-11-11 00:00:00 -05 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started
2021-11-11 00:01:14 -05 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
Duplicati.Library.Interface.UserInformationException: Unexpected difference in fileset version 0: 11/2/2021 8:50:14 AM (database id: 1), found 95877 entries, but expected 95878
at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency (System.Int64 blocksize, System.Int64 hashsize, System.Boolean verifyfilelists, System.Data.IDbTransaction transaction) [0x0036e] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Backup.BackupDatabase+<>c__DisplayClass34_0.<VerifyConsistencyAsync>b__0 () [0x00000] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Common.SingleRunner+<>c__DisplayClass3_0.<RunOnMain>b__0 () [0x00000] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Common.SingleRunner.DoRunOnMain[T] (System.Func`1[TResult] method) [0x000b0] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.BackupHandler.RunAsync (System.String[] sources, Duplicati.Library.Utility.IFilter filter, System.Threading.CancellationToken token) [0x0034d] in <1d9349a5d6874088879a75d074c92b62>:0
2021-11-11 00:01:16 -05 - [Information-Duplicati.Library.Modules.Builtin.SendMail-SendMailComplete]: Email sent successfully using server: smtp://smtp.gmail.com:587?starttls=always
2021-11-12 00:00:00 -05 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started
2021-11-12 00:01:09 -05 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
Duplicati.Library.Interface.UserInformationException: Unexpected difference in fileset version 0: 11/2/2021 8:50:14 AM (database id: 1), found 95877 entries, but expected 95878
at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency (System.Int64 blocksize, System.Int64 hashsize, System.Boolean verifyfilelists, System.Data.IDbTransaction transaction) [0x0036e] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Backup.BackupDatabase+<>c__DisplayClass34_0.<VerifyConsistencyAsync>b__0 () [0x00000] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Common.SingleRunner+<>c__DisplayClass3_0.<RunOnMain>b__0 () [0x00000] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.Common.SingleRunner.DoRunOnMain[T] (System.Func`1[TResult] method) [0x000b0] in <1d9349a5d6874088879a75d074c92b62>:0
at Duplicati.Library.Main.Operation.BackupHandler.RunAsync (System.String[] sources, Duplicati.Library.Utility.IFilter filter, System.Threading.CancellationToken token) [0x0034d] in <1d9349a5d6874088879a75d074c92b62>:0
2021-11-12 00:01:11 -05 - [Information-Duplicati.Library.Modules.Builtin.SendMail-SendMailComplete]: Email sent successfully using server: smtp://smtp.gmail.com:587?starttls=always
You might find that you need to start a fresh backup.
I have done this multiple times and still get the same error.
Maybe split your files into about 100-130GB backups at most by creating backups that only deal with certain folders each.
That seems like an unreasonable constraint for a backup client worth it’s salt. I’m working with a network attached storage device that is actively being used by an office with ~20 workers. Restricting their usage of the storage to adhere to the backup client limitations is not an option.
One thing you could look at is whether this one is also in a compact, e.g. does checking no-auto-compact postpone it until you manually use the Compact now button.
I have tried this too. It doesn’t seem to make any difference whether or not the no-auto-compact option is checked.
I think you can use the Verify files to try a verification like you’re having fail under the automatic one. If you’re lucky enough to get the usual job log, it breaks down the individual pieces of a run (such as compact) but it also may be skipped on failed backup.
I have done this as well. The logs always stop after the unexpected difference error. Not very helpful.
Previous rule-of-thumb was 1 million blocks per backup, but more recent testing here says go a bit higher.
Currently, I use the default remote volume size of 50MB. Would you suggest a change? (The office has a dedicated fiber line, so connection speed and reliability are not an issue).