08-28-2010, 01:29 AM

Hi. VERY new to Mac. I would like the applications to run on the SSD drive and the data to store on the TB drive.
However the "structure" for data exists on the SSD and nothing is on the TB drive.
How do I replicate that structure on the TB drive?
Do I have to tell every application to put data over there?
In Mail for instance, where is it storing the data and how do I change it?
Sorry for the newb ?s...I'll get there eventually...
Scott

08-28-2010, 04:17 AM

By and large, this is a bad idea.

First off, you are on a Mac. It does not require so much "management" as a PC does.

Second, some apps depend on the data being on the boot drive (as an example, fonts). Most of the ones that generate a lot of data (iPhoto, iTunes, iMovie as examples) certainly do allow you to store those libraries on external drives if you like, and some (like Photoshop) even let you assign external disks as scratch space.

But apart from the obvious culprits, most applications one uses generate negligible amounts of data. All the documents you have ever written in your entire life wouldn't fill up an 80GB drive. For many people, make that 40GB.

All my email for the last three years -- including every attachment I've gotten (I get about 100 emails a day, often with graphics file attachments) adds up to 5.77GB on a 320GB drive.

Bottom line: relax. You just don't need to fret about this stuff, as there's really only a few applications that even have the POTENTIAL to fill your HD and every one of them lets you store data wherever you want very simply and easily.

08-28-2010, 02:11 PM

Originally Posted by chas_m

Bottom line: relax.

Ha. My neuroses generally won't permit...but I'll make a focused effort! I wasn't worried about the space so much as I was about simplifying the picture for back-ups. Also I had an internet-induced worry that excessive write/re-write to the SSD would degrade it's performance. I know, I know...

08-28-2010, 03:21 PM

The way Mac manages user data is that most everything goes to your home directory. You can follow this procedure to put your home directory somewhere else
10.5: Easily change the location of your home directory - Mac OS X Hints)

Basically copy your home directory to the volume you want and do this

sudo ditto -rsrc "/Users/username" "/Volumes/path-to-new-folder"

Then ctrl-click your user name in System Preferences -> Accounts to get to advanced options. From there you can change your home directory.

Log out - log back in. Just make sure your external drive is always available. For an iMac it should be fine - probably a bad idea for laptops.

08-28-2010, 09:35 PM

Originally Posted by IvanLasston

Just make sure your external drive is always available.

I think Ivan is REALLY underplaying the consequences of what happens if any app calls for the home folder and it isn't where its expected to be.

Suffice to say you REALLY don't want to untangle those knots, which is exactly why I strongly recommend NOT doing this.

08-28-2010, 10:16 PM

I may have underplayed - all your temp files, all your downloads, scratch disks, pretty much default to your home directory.

Also don't forget that if your program is write intensive, you may see slowdowns - a USB external drive max bandwidth is 480Mbps - SATA is 3Gbps.

I'm just saying it is possible and I could see wanting to do it especially for a desktop system. As long as you are not removing the drive it should be fine.

08-28-2010, 11:14 PM

Originally Posted by IvanLasston

As long as you are not removing the drive it should be fine.

I'll investigate further...both the SSD and the 1TB drive are INTERNAL so they should always be there.

Not looking to make the mac behave in a manner it wasn't designed to, but this looks interesting. Thank you both for your thoughtful answers.