space on external hard drives

[Sossity Corby]

should I leave a little "breathing room" or free space on my external hard drives? right now I have all my photos & movies files on 3 different external hard drives. Is there an approximate amount of space that I should leave free on my drives or should I fill them to total capacity?

I do not have my own computer so all my files are on these of which I plug into the "host computer" in this case my mothers to work with my photo & movie files.

Also, My arrangement for the 3 drives so far is; external hard drive 1; for photos only; where on a given date I only took photos; consisting of my camera original jpegs & their derivatives;( tiffs & jpgs,)  external hard drives 3 & 4; where on a given date I shot mpg movie files from my still camera  & photos taken along with movie files, consisting of my camera originals & derivatives,(jpgs & tiff files); I am just getting started on the "bucket system" & was wondering if I have a good arrangement of my drives. I have found the movie files take up much more space so I decided to keep these on a separate drive from my photos.

so far I have only shot jpg originals from my cameras, so for my photos only drive no 1 should I use CD or DVD as a back up medium? this will determine bucket sizes for my external hard drive 1. The derivatives on drive 1 consist of jpgs & tiff files.

Sossity

[peterkrogh]

I'd say to keep at least 5% freeon external drives, and I personally tend toward 10%.  Keep in mind that free space is not as necessary if you are only storing unchanging files on these drives, and not stuff that is rewritten all the time.

The need for free space goes up when a lot of files get swapped around on a drive, and goes down for drives that only get written to once (and updated infrequently).  It goes down even futehr for backup drives which may never get written to again. (Other than disk utility chores.)

Boot drives and scratch drives need lots of free space since files are getting swapped around a lot.  Working files drives also need lots of free space since files are moved in and out lots. Leave 20% or more free for these drives.

As to your other questons, I think you can answer those better yourself.
Peter

[michael_stewart]

You need at least 15% to safely defrag a hard drive.  Many experts recommend 30% free space.  I've seen all kinds of problems with drives and memory cards that get full, so I would leave plenty of head room.