Re: Plans for 1.8+ (2.0?)

[Bill Hacker <wbh@xxxxxxxxxxxxx>]

Thomas E. Spanjaard wrote:
> Stilyan Tsenov wrote:
> > I can't uderstand whether snapshots are filesystems or files ?...or
> > just both possible ?
>
> A snapshot of a filesystem needs support from the filesystem to be 
> snapshottable, e.g. temporary suspension of all activities on that 
> filesystem while the snapshot-taking is in-progress.
>
> Cheers,

. .. except for Plan 9, where the 'snapshot' was basically a byproduct of the way 
updates were done - i.e. change (and date) only what HAD changed, preserve all 
else - even if no longer 'valid'.

By selecting a date/time, the 'collection' of data current at that time could be 
had - ergo instant de fact 'snapshot', and to very fine granularity.

An RDBMS where all records are timestamped and never 'vaccumed' can do much the 
same - a device we used for years to 'what if' telco service-mix pricing:

- current, historical, or anticipated telecoms traffic

could be 'billed at'

- current, historical, or anticipated rates.

Made comparison much easier w/r adjusting for this and that..

Bill