Re: About network failures while uploading

[tarsnap <tarsnap@infopower.nl>]

On Sat, 8 Mar 2014 14:41:50 +0000
Colin Percival <cperciva@tarsnap.com> wrote:

> On 03/08/14 06:29, tarsnap wrote:
> > Continuing a thread from Jul 2011, I would like to know if in case
> > of backing up 1 file (>1 GB) and tarsnap quitting due to 'Too many
> > network failures', parts of the file are retained on the server,
> > and re-used when repeating the backup command in tarsnap.
> > 
> > I got the uncomfortable feeling that the error message I got: "Error
> > closing archive", means 'NO'.
> 
> Probably.  There's a very slim chance that the final transaction
> commit request got through to the server but your connection died
> before the acknowledgement came back.
> 
> > Further I wonder why the backup fails already after 4 errors
> > looking up betatest-server.tarsnap.com.
> 
> It's the other way around -- when a connection is failing, tarsnap
> will retry several times before giving up; and as part of those
> retries it will perform new DNS lookups (and warn when those fail due
> to your internet connection being down).
> 
> > This way, with my quite unstable network
> > connection, I'm afraid the uploading will never complete.
> 
> I'd recommend using the --checkpoint-bytes option with a fairly low
> setting (e.g., --checkpoint-bytes 32M) so that you'll have lots of
> checkpoints created.  That way when an archive fails you'll still have
> the first section of the archive stored -- and that data can then be
> used for deduplication purposes when you create another archive, which
> will make future archives use less bandwidth and complete faster.

Thanks for your reply.
So I have to do 2 things:
1) add the checkpoints option
2) create another (NOT the same) archive?

> Of course, finding an internet connection which doesn't break for 5
> minutes at a time would be ideal.  (5 minutes is how long tarsnap will
> keep on trying to reconnect.)

The internet connection breaks down when the power goes out, which
happens quite frequently: 2 times a day for 2 hours each.
The laptop runs longer than 5 minutes on its own battery, which means
tarsnap will always 'give up'.

Which brings me to the following feature request: 
A command line option to set the
'retry time' (from 5 min. to inf., and frequency--if not automatic as
function of 'retry time').

tnx