[Box Backup] manual snapshot problem

[Chris Wilson]

Hi Torsten,

On Sat, 18 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?

> I do not know if this works for me. Does UpdateStoreInterval only influence 
> the backup interval? 

Yes, as far as I know.

> I mean, is
>  "Automatic Backup with UpdateStoreInterval=3600"
> and
>  "AutomaticBackup=no, UpdateStoreInterval=99999999999999 and manual snapshot 
> once per hour with crontab"
> exactly the same?

It's almost but not quite the same. There is some randomisation of times 
introduced into the AutomaticBackup mode which is supposed to prevent 
clients from falling into lock step with each other. Also, the latter does 
rely on external influence, whatever that is, to kick off a backup, and 
it's possible to do something much more sophisticated than just using cron 
to do that.

> But i think this configuration is not really intuitive. I mean it could 
> be difficult to describe how this works. Perhaps another 
> ConfigurationOption (e.g. ImmediatelyRestartSyncOneErrrors) would be 
> clearer?

That could work, but I'm reluctant to introduce a new option until I've 
exhausted all options to make the default behaviour work for everyone.

The idea of the current behaviour is that if you requested a backup, and 
it didn't complete successfully (e.g. the connection was interrupted), 
then it should keep retrying until it does. I can see that there might be 
a case for a retry limit here.

It should already ignore errors like failures to read files, and only do 
this if something really bad like an exception causes the backup to fail 
early. Is this a case where your DSL provider is killing your connection? 
If so, then don't you want to try again immediately and keep trying until 
you've completed a backup?

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?

Cheers, Chris.
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