View Full Version : multiple partitions on a mirror?

10-02-2007, 09:34 AM
I just was told that it was possible to create a (OSX software) mirror and put two partitions on it. (one for OS and one for data) Now while I think this somewhat defeatus the purpose of separation of OS and Data, I did go looking for it but the partition option (and most others) are not available when a raid volume is selected.

Is there something I am overlooking? Or does this have to be done in terminal with diskutil?

n/m found it. The trick is to partition BEFORE raiding. If you have two drives and want to make two partitions on the one raid, you split up the two drives both the same, (lets say you have a pair of 500's and you want a 50gb and a 450gb mirror) you partition both individually as 50/450, and then create two separate mirrors with similar size partitions. (drag the partitions into the raid list instead of the drives as was previously required) This enhancement was apparently added sometime in 10.4's disk utility. (possibly when raid v2 was enacted?)

This will do nothing especially useful for redundancy, but will help if you need to isolate your data, such as separate OS from data, or have one drive with permissions off, etc.