Probabilmente vorrai controllare questo sito web per la maggior parte delle informazioni, ma ecco la risposta alla tua domanda, citata dal sito web sopra:
1. Quanto è grande l'unità di cui ho bisogno per Time Machine?
A general "rule of thumb" is, to keep a reasonable "depth" of backups,
Time Machine needs 2 to 4 times as much space as the data it's
backing-up (not necessarily the entire size of your internal HD). Be
sure to add the size of the data on any other drives/partitions you
want to back up.
But this varies greatly, depending on how you use your Mac. If you
frequently add/update lots of large files, then even 5 times may not
be enough. If you're a light user, you might be able to get 1.5 times
to work, but that's subject to problems any time a large backup is
needed.
And, of course, the larger the drive, the more old backups Time
Machine can keep for you. A drive that's too small may only have room
for a few weeks (or even days) of backups.
Unfortunately, it's rather hard to predict, and most of us have a
tendency to add more and more data to our systems over time, so if in
doubt, get a bigger one than you think you need now.
Also, there are some OSX features and 3rd-party applications that take
up large amounts of backup space, for various reasons. See question
9 for details.
This is a trade-off between space and how long Time Machine can keep
its backups, since it will, by design, eventually use all the space
available. But it won't just quit backing-up when it runs out: it
starts deleting the oldest backups so it can keep making new ones.
Thus, the more space it has, the longer it can keep your backups.
If your backup disk is on the small side, and Time Machine needs to do
a very large backup, either because you've added or changed a lot or
done something like an OSX update since the previous backup, you may
get one of the messages in Troubleshooting item #C4 (which one
depends on exactly what happened, and which version of OSX you're on.)
La mia risposta
Then it'll only take a snapshot that's about 120GB in size, and while that same snapshot will grow over time as I take more recent snapshots of my system, it will never go beyond 500GB because that's the maximum size of my internal HDD.
No, non proprio. Il disco rigido da 1 TB sarà riempito perché Time Machine conserva i backup e li elimina una volta riempito il disco rigido. C'è più di un backup memorizzato su quel disco rigido. Come sottolineato da noi, Time Machine consente di ripristinare un backup precedente, poiché Time Machine può conservare 7 o 8 backup su quel disco rigido da 1 TB.
I'm asking this because I want to know if I should use a separate external HDD for storing my actual files.
Sì, dovresti. Dovresti dedicarti a Time Machine. Ecco la risposta citata da 3 nel sito web che ho linkato sopra:
3. Posso usare il mio disco di Time Machine per altre cose?
Yes. Time Machine will not delete anything you put there. But it's
not a good idea to put anything else important on the same physical
drive, unless you back it up elsewhere. When (not if) that drive
fails, you risk losing it.
If you want to do this anyway, it's much, much better to partition an
external drive into 2 (or more) parts, also called volumes. Assign
one to Time Machine, for its exclusive use for backups; use the other
partition(s) however you want. To use a new drive, or one you don't
mind erasing, see question #5. To add a partition to an existing
drive that already has data on it, see question #6.