Re: Backup systems
On 2 Sep 2023 14:49 -0700, from dpchrist@holgerdanske.com (David Christensen):
> So, 693 GB backup size, 98 backups, 67 TB apparent total backup storage, and
> 777 GB actual total backup storage. So, a savings of about 88:1.
>
> What statistics are other readers seeing for similar use-cases and their
> backup solutions?
8.07 TiB physically stored on one backup drive holding 174 backups;
11.4 TiB total logical (excluding effects of compression) data on the
source; 7.83 TiB hot current logical data on the source (excluding
things like ZFS snapshots and compression).
Which by your way of calculating seems to work out to an about 246:1
savings compared to simply keeping every single copy in full and
uncompressed. (Which would require almost 2 PB of storage.) But this
figure is a bit exaggerated since there are parts of the backups that
I prune after a while while keeping the rest of that backup, so let's
be very generous and call it maybe a 100:1 savings in practice.
Which is still pretty good for something that only does raw copying
with whole-file deduplication.
I have a wide mix of file sizes and content types; everything from
tiny Maildir message files through photos in the tens of megabytes
range to VM disk image files in the tens of gigabytes range, ranging
from highly compressible to essentially incompressible, and ranging
from files that practically never change after I initially store them
to ones that change all the time.
--
Michael Kjörling 🔗 https://michael.kjorling.se
“Remember when, on the Internet, nobody cared that you were a dog?”
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