Invisible wrote:
> Warp wrote:
>> Invisible <voi### [at] devnull> wrote:
>>> The new global backup procedure that's being drafted will mean that 
>>> backup tapes are stored *forever*. (With the corresponding 
>>> astronomical increase in expenditure on new tapes and physical 
>>> storage space. But hey, it's not my money.)
>>
>>   As I said, that doesn't need to be the case. For example daily backups
>> worth an entire month can be stored in an incremental backup system. This
>> way only one backup per month has to be stored permanently, but it will
>> still allow restoring any single day of that month, and the size of the
>> backup will be only somewhat larger than the size of the entire system
>> being backed up. (Basically it's the entire system plus modifications
>> during that month.)
> 
> The plan is to store only the monthly full backup tapes - so that's only 
> actually 12 tapes per year. Of course, in 20 years' time we'll have 240 
> of the suckers - not to mention the fact that in 20 years' time, people 
> probably won't be using LTO1 any more so there probably won't be any 
> equipment that can still read the tapes thus making their retention 
> utterly pointless. But in the main it's a sound system...


Back when I was helping to build cars I deleted a file and only noticed 
that it was gone something like 6 months later.

Luckily, their rotation kept some very old tapes.

I don't remember specifically, but their rotation was something like:

daily for a month
after the month, just keep the weekly tapes
After 3 months keep only the monthly - permanently

Or something roughly like that.
It won't catch everything, but it catches most things.



Tom

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