Re: [Duplicity-talk] --file-to-restore without passphrase

[edgar . soldin]

On 24.11.2014 18:31, Grant wrote:
>>>>>>>> Is there a way to verify
>>>>>>>> my entire archive instead of one dir/file at a time?
>>>>>>
>>>>>> OK, I just needed to add 'verify' and move the URL before the other
>>>>>> paths in the backup command I'm already using.  If that comes back OK,
>>>>>> can I consider my backup archive uncorrupted?
>>>>>>
>>>>>> I read somewhere that duplicity requires a periodic full backup
>>>>>> instead of only incrementals.  Is that true?
>>>>
>>>> no.it is suggested however as one corrupt volume will make all backups 
>>>> afterwards in that chain unrestorable as well.
>>>
>>>
>>> Is doing a periodic full verify a good substitute for a periodic full 
>>> backup?
>>>
>>
>> do the math. the more volumes, the more likely that one might get corrupted- 
>> the only way to keep the volume count small is a short chain, hence a 
>> preriodical full to start a new.
>>
>> verification should be part of backup routine anyway. after all you value 
>> the data enough to make backups.
> 
> 
> So I'm sure I understand, I can be sure there is no corruption
> immediately after completing a full verify, 

yes

>but starting fresh with a
> full backup yields fewer volumes which means there is less chance of
> corruption in the time between my verify operations?
> 

yes. e.g. your average backup yields 100MB in changes per day. with a default 
vol.size of 25MB that would amount to 100/25*365 ~ 1300 volumes.
now assume you would start a full every month. that will get you 1300/12 ~ 110 
volumes per month.

so you could say that the probability of corruption in the full year chain is 
12times higher than in each of the monthly chains alone.

also, in case some file get's corrupted you will still have a working chain 
from before or after the broken chain.

you might wanna consider using par2+ backend to prevent corruption. see manpage.

..ede/duply.net