Partition or not?

January 12, 2006 8:33 AM

Partitioning an external hard drive for a Macintosh Powerbook? Why?

Keep in mind that I am not much of a tech-head, but I know my way around the Mac I have at home and at my office, at least a little.

I recently bought an external 160 gig firewire hard drive. I plan to use it mainly as a place to store and play MP3s. I'll probably store some videos there eventually as well.

I read in the manual that you can partition the drive. I can't find much simple info as to why I would want to do this. I understand the basics of what partitioning is, but does it make sense to partition a drive used just for storage?

posted by jeff-o-matic to Computers & Internet (9 answers total)

Earlier file systems had a partition size limit. This meant that if you bought a larger drive, you had to divide it into several partitions.
posted by reverendX at 8:37 AM on January 12, 2006

Partitioning a drive just divides it into distinct sections that function essentially independently - as far as the system is concerned, each partition is an independent hard drive (and that's how they appear on your desktop).

In the pre-OS X days (and for some, still today) one very good reason to partition a drive was to store things such that if one partition became corrupt, you wouldn't face losing all of the data when you reformatted the partition (since things were spread over several partitions, likely). That is not, to me, much of a reason to do so now, but some will disagree (and those points of view are reasonable).

In the past, and on some platforms still, people who wish to run multiple OSs also partition the HD and use each partition as the location of a different environment. You can choose which partition to boot from (since they act as independent HDs and you can boot from a firewire disk) and so if you had some form of Linux installed you might want that to live on its own partition. In the Mac OS X world I doubt many people bother.

For you, there would be one main reason to partition your large external HD - for backup purposes. Super Duper, for example, is a relatively new backup utility for the Mac that essentially clones, in a bootable, completely functional fashion, your main HD to another drive. To do this, when it gets started it generally erases everything on the destination disk. If you used your whole 160G drive, then, you'd be able to use it without partitioning, but you wouldn't really be able to use the other portions of the disk for other things. On the other hand if you made a partition large enough to hold the entire backup you would likely still have another huge partition left to leave mounted on your desktop to use as regular everyday storage space.

Hint: If you do clone your internal HD to a backup partition, make sure Spotlight knows not to index it for searches, or else you'll get dupes of every file on your internal drive in your search results. Huge pain in the butt.
posted by mikel at 8:48 AM on January 12, 2006

The partition table holds information such as "how big of a space are we dealing with" and "what kind of filesystem are we using". Even if you're only using one partition on a massive drive, the partition table still holds crucial information which your OS requires to properly interface with the drive.
posted by jaded at 8:49 AM on January 12, 2006

Unless you have a specific reason for doing it, no, you don't want to partition it.

I partitioned my 250 GB external drive because the one partition is going to be used to dupe an 80 GB internal hard drive in my iMac, and the remaining is used for extra storage. If you aren't going to do something like that, don't bother.

If you *do* want do dupe your PB hard drive, in addition to storing media, then yes, partition it. Some (all?) of the duping software requires it.
posted by teece at 9:41 AM on January 12, 2006

Conceivably, one might do this to create a scratch disk for Photshop or After Effects work.
posted by Scoo at 9:51 AM on January 12, 2006

I used to partition because I liked to categorize my files at the drive level. So I had a partition for photos, another for music, another for videos. I don't do this anymore because you have to guess at the right sizes and it's very easy to get them wrong. You also end up moving things between partitions when you need a big chunk of contigous space.

You avoid these issues by using a single partition. Now I just categorize using top-level folders.
posted by smackfu at 9:52 AM on January 12, 2006

Seconding the backup. 60GB of my 160GB external is partitioned to be a mirror backup of my regular drive (Super Duper is great for this); the other 100GB is used for media.
posted by thejoshu at 9:52 AM on January 12, 2006

smackfu's comment about guessing sizes is non-trivial. When I came to Linux years ago, I partitioned my drive into several areas, based on usage (one for home, one for var, one for usr, etc.) There are decent reasons for doing this, and it was the conventional wisdom.

However, in the long run, the partitions were a giant pain in the ass -- because it's pretty hard to effectively guess your usage needs for years at a time, which is how long my Linux hard drives get used for. So while there were real benefits to partitions based on usage, to me they are mostly nullified by the rigidity of the system that you pick. (Also, the size of modern hard drives, and the availability of backup hard drives, made the benefits of partitioning mostly vanish).

Any more, except for very specific things, I don't partition drives. The times I will partition are niche: a Windows and Linux partition for a dual-boot machine, a swap partition for Linux, a dup-backup partition for the Firewire drive I use with my Mac, etc. I no longer think it makes sense to do it solely on thy type of data I expect to put on the drive.
posted by teece at 10:04 AM on January 12, 2006

As the other posters have said, unless you have a specific reason to partition, it's not worth it. Back in the old days of the Mac OS, I used to partition my drives—it made slightly more efficient use of the small hard drives we had back then (due to block sizes), was some protection against soft failures, and (I think) made things run a little faster. These days, those reasons are pretty much moot, and you're left dealing with inflexible partition sizes.
posted by adamrice at 11:18 AM on January 12, 2006