Re: [rdiff-backup-users] How much extra space should there be on a target file system?

[Patrik Dufresne]

Hello Ted,

As you mentioned, It depends alot on your specific usage and how long you
want to store the data.

> Anyway, I am wondering if there is any guidance on how much larger the
target file system should be compared with the source file system when using
rdiff?

Here the rules I have when I have little information about he filesystem
usage:
1. For business, I multiply the average data size by how many year they
want to keep.
So if the business have around 150GiB of data and want to keep them for 5
year: 150 x 5 = 750GiB is a good start. That also account for the business
growth and files changes.

2. For desktop users is different, the data change less often. I usually
just double the capacity. For a user with 250GiB, I will plan 500GiB.

Hope it's helping you to plan the capacity.

--
Patrik Dufresne Service Logiciel inc.
http://www.patrikdufresne.com <http://patrikdufresne.com/>/
514-971-6442
130 rue Doris
St-Colomban, QC J5K 1T9


On Sun, Sep 1, 2019 at 4:55 PM Mike Fleetwood via rdiff-backup-users <
address@hidden> wrote:

> On Sun, 1 Sep 2019 at 19:39, Theodore Wynnychenko <address@hidden>
> wrote:
>
> > Hello
> >
> > I have been searching for an answer or guidance to this question, but
> have
> > not been able to find anything, so I will ask here.
> >
> > I am sorry if it has been asked/answered before.
> >
> > In any case, I am planning on "updating" my backup hardware, and will
> > probably switch from rsync to rdiff (I have used rsync for many years,
> and
> > have been happy with it, except for that one time years ago when I
> deleted
> > a
> > bunch of files and did not notice until about a day later, and 10 minutes
> > after the final backup had been synced - a bit disappointing).
> >
> > Anyway, I am wondering if there is any guidance on how much larger the
> > target file system should be compared with the source file system when
> > using
> > rdiff?
> >
> > Clearly, rdiff stores more information, so, in theory, if you have two
> file
> > systems of exactly the same size, and the source is completely full, then
> > rdiff would have nowhere to store any historical changes.
> >
> > Is there a rule-of-thumb, or some sort of calculation that will give
> > guidance on how much extra space there needs to be on the target file
> > system
> > to reliably not have an instance when the target file system becomes
> full,
> > while the source still has space on it?
> >
> > It seems this would be based on the frequency of updates, the size of the
> > file system, the number and size of files, the types of changes made to
> > those files, how long backups are maintained, and probably other things.
> >
> > I am not looking for anything exact, more just a way to guesstimate.
> But,
> > I
> > am also not opposed to math either, if there is a calculation that can
> help
> > determine the target file system's appropriate size.
> >
> > Thanks
> > Ted
> >
>
> Just a user here who backups up their home Linux desktop using
> rdiff-backup.
>
> So it all depends on your rate of change of backed up data and how long
> you want to keep previous backups for.
>
> As an example here are some figures from my daily backup:
>
>     Backup                   Size    Pct
>     --------------       --------    ----
>     Current mirror       42.8 GiB    100%
>     Day 406 increment    65.4 GiB    150%
>     Day 804 increment    87.2 GiB    200%
>
> So for *MY* data and *MY* rate of change, 150% is enough for over a year
> of daily backups.  Make sure your backup file system has enough inodes
> as well as free space.
>
> Mike
> _______________________________________________
> rdiff-backup-users mailing list at address@hidden
> https://lists.nongnu.org/mailman/listinfo/rdiff-backup-users
> Wiki URL:
> http://rdiff-backup.solutionsfirst.com.au/index.php/RdiffBackupWiki