How Can Multiple Hard Drives Act As One

c.greene914

macrumors regular
Original poster
Jun 3, 2007
104
0
Here is my dilemma, I want to use a Mac Mini for a dedicated media server. However right now I have two 750gb hard drives, both reasonably full, meaning soon I will have to buy a third external HDD. The Mini has 4 USB ports on the back. Is there a way to plug multiple external HDDs into multiple USB ports and have them act as one huge HDD?

The reason I need this is because I plan to keep everything in iTunes and just leave it open/running. In order to do this I have to have one iTunes library and locate it in one place, not four different library folders spread out over four different HDDs.

Can someone help me with this, or recommend a better way to do it?
 

Queso

Suspended
Mar 4, 2006
11,824
7
You can do it in Disk Utility by setting up a RAID array, but to be honest you'd be better off buying an external RAID enclosure and mounting drives in there. Try and use RAID5 if possible. If your volume spans multiple disks on a normal RAID0 array and one of them fails you lose the entire volume. On RAID5 you can lose a disk and your data remains intact, which means you can rebuild the array simply by replacing the faulty drive.

The downside of RAID5 is that you need a minimum of three disks and one of them is effectively wasted spacewise. So three 750GB disks would give you 1.5TB, not 2.25TB. You would also need to back your data up off the disks before creating the array.
 

c.greene914

macrumors regular
Original poster
Jun 3, 2007
104
0
I back everything up on disc so I'm not to concerned with HDD failure. The reason I don't want to mount everything in one RAID array is both of my HDDs are still under the Seagate 5-year warranty and putting them in another case will void that. The 5-year warranty is one of the reasons I bought a Seagate so I would like to keep that. If I can keep them in separate cases and just configure them to RAID 0 in disk utility, that would be my best option I believe.
 

mkrishnan

Moderator emeritus
Jan 9, 2004
29,777
12
Grand Rapids, MI, USA
If I can keep them in separate cases and just configure them to RAID 0 in disk utility, that would be my best option I believe.
I'm pretty sure there's nothing that stops you from doing this. Someone blogged about taking four iPod Shuffles (when they first came out), putting them on a USB hub, and making a RAID out of them. So the fact that they're in different cases or on different controllers doesn't seem to matter to Disk Utility in terms of making a software RAID.
 

balamw

Moderator
Staff member
Aug 16, 2005
19,368
973
New England
Note too that unix based OSes don't really follow the same concepts as Windows w.r.t. "drive letters". Yes, they auto mount at separate mount points in /Volumes, but you can easily make a symbolic link to a file or folder on a volume2 that will be largely indistinguishable from a file on volume1. Plus you can even make the mount point for volume2 be somewhere on volume1.

Relevant links:

http://www.macosxhints.com/article.php?story=2001110610290643

http://www.macosxhints.com/article.php?story=20050805062520199&query=mount+point

B