[Box Backup] manual snapshot problem

[Chris Wilson]

Hi Torsten,

On Tue, 21 Oct 2008, Torsten wrote:

> > > You are right. I have errors in the backup runs. I still have to locate
> > > them ;)
> >
> > Doesn't the backup output/system logs help?
> 
> Not really. It only shows an
> 
> bbackupd[9649]: WARNING: Exception thrown: CommonException(OSFileError) at 
> BackupClientFileAttributes.cpp(307)
> bbackupd[9649]: ERROR: Exception caught (Common OSFileError (Error accessing a 
> file. Check permissions.) 1/9), reset state and waiting to retry...

Thanks, I found a number of places in BackupClientFileAttributes.cpp where 
the name of the file causing the error was not reported. I've fixed them 
all and will commit a fix very shortly.

> But i do not know what file has wrong permissions. ExtendedLogging did 
> not help.

ExtendedLogging is only protocol logging, it would not help much in this 
case (it might identify the directory where the error occurred). 
LogAllFileAccess might help, however.

> > Is this happening in the middle of uploading a large file? Is it only a
> > problem because Box Backup doesn't know how to resume partial uploads?
> 
> But i think my problem is no connection problem. My problem at the moment is 
> that at the box backup server i have to pay for traffic. And so restarting 
> backup run immediately after error generates lot of traffic.

The problem seems to be that we discard all cached state when this kind of 
error occurs, which means that it has to be reloaded from the store. We 
should probably catch this kind of error and deal with it better, for 
example by continuing the backup. Please could you run bbackupd with the 
-V option, which should hopefully generate a stack trace when this error 
occurs, and give me the stack trace so that I can figure out where to 
catch the error?

> Restarting Backup on errors after UpdateStoreInterval would be a 
> solution for me. How complicated is it to implement this function?

Not very complicated, I think I will do that.

Cheers, Chris.
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