Two partitioned drive questions: can i mount both at once AND do i need extra space?

So, I have a 6tb drive I got for film editing. I have two questions before I partition and fill it up:

1 - I am using the drive for a film project I already started with two other drives. What I want to do is partition the new drive into 3, using two of the partitions to duplicate the drives I already have. This makes sense if I can mount multiple partitions at the same time from the same drive? Can I do that? I assume so. But reading online i haven't found conformation.

2 - I know the rule of thumb is to keep 10% of a hard drive free. If I partition the drive, do I need to keep 10% of each partition free or is 10% overall OK?

1. Each partition will mount and show separately on your Desktop.

2. The 10% rule only(AFAIK) applies to your boot drive, as the OS uses this for temporary storage.

Really?! I thought it applied to external drives too. That's not the case?

oxband said:

Really?! I thought it applied to external drives too. That's not the case?

Click to expand...

Not unless you have them as a Bootable Drive. If you want to Boot from them, then yes 10% around here people will say 20%Minimum (but thats another story) as they are in essence your Mac OS you are working on, so you are going to need that space for Swap Files, and to let the OS do what it needs to do to run efficiently
If they are just for storage, fill it up until you have 1 MB left and you will be OK.

The other situation where blank space might be beneficial is with programs that let you control where they store the "scratch disk". This space for temporary files is different from that used by the OS.

I am thinking that I had this problem with some versions of Photoshop. Not sure if it is still an issue since I am using an older version. Things seemed to slow down when the scratch disk got too full. Bet there are other programs out there with similar setups.

This blows my mind. I had no idea i didnt need to leave free space. Thanks for the heads up!

I'm am one of those that keep their HD boot drives at 35-40% free space minimum.
External "storage only" drives I keep at 1% or 1 GB minimum whichever is larger.
I've never allowed a drive under 1GB free space since the advent of 30GB+ drive sizes.
(Just my own personal rule of thumb because I'd just as soon not find out what happens to a full drive.)
Never used a scratch disk, but would guess best scenario would be to maintain ample free "contiguous" space for your projects.