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Re: Using wildcards to remove archives
On Fri, Mar 15, 2019 at 12:42:39AM -0700, Craig Hartnett wrote:
> On Thu, 2019-03-14 at 20:21 -0700, Graham Percival wrote:
> > $ tarsnap -d --archive-names todelete.txt
> Brilliant! Almost exactly what I was looking for and it worked
> perfectly. Thanks Graham. Only problem is now you're making less money
> from my having previously over-archived.
Unless your data changes a lot, it probably doesn't make much of a
difference to the amount that you pay. For example, let's look at
my personal data that I back up. I started in July of 2012, and
made 3 archives:
$ grep "2012-07" archives.txt > check.txt
$ more check.txt
$ tarsnap --print-stats --archive-names check.txt
Total size Compressed size
All archives 31530638982 21480417909
(unique data) 1590891610 1025306568
all-2012-07-14 388384107 297320442
(unique data) 1970795 838647
all-2012-07-15 387590611 296985868
(unique data) 712486 235231
all-2012-07-28 391691883 299653912
(unique data) 2165719 1050518
What we care about is the "(unique data)" and the "Compresed
size". Look at my very first archive, all-2012-07-14: 838647 (or
slightly less than 1 MB).
Because I've lazily not bothered to delete that archive, how much
money have I paid to Tarsnap in the past 7 years?
Enter an expression to evaluate, q to quit, or ? for help:
-> 838647 * 250 * 10^-12 * 7*12
Less than two cents. Deduplication is amazing!
Sure, I sometimes get OCD twinges at having all these old useless
backups floating around (although I only back up approximately 1
per month, so it's far less than you'd imagine). But whenever I
look at the math of how much I'm spending, vs. the possible risk
of my deleting an archive that I might end up needing later... I
figure it's just not worth it.
Of course, everybody's data and usage patterns are different. If
you're curious, I encourage you to run this experiment with your
own data. For any given archive, how much will it cost to save
that unique compressed data for 5 or 10 years?