Adding Fusion Drive on mid 2010 iMac 27" using 120 GB SSD drive and 4TB HDD

My Problem

Wanted larger local data internal repository with rapid loading apps/programs. Fed up of slow wifi and ethernet network filesystem update and waiting ages for file updates and backups. Went for Fusion drive using SSD and 4TB Seagate HDD

My Fix

Nothing exploded!. Went back together perfectly. Need plenty of time with no interruptions and another source for information such as iPad. Initially set up as a case-senstive HPS+ volume which lead to problems with Adobe products not loading or installing. As yet none of their products will work on a case-senstive volume. Wanted this as planned to use as a server but what the hell. Had to recreate a non-case-sensitive HPS+ volume and restore again to get Adobe stuff working again.

No problems with fans going flat out afterwards.

My Advice

Need to have fast Firewire link to backup before and restore after Fusion volume created if you have alot of data. It takes hours to restore. Using TimeMachine restore over network will take days to complete

Fusion volume is supposed to put system files on SSD leading to fast loading frequently used programs. User data directories on HDD. Performance degrades if you plan to edit huge video files.

Ensure enable TRIM (http://www.nick-p.info/enabling-trim-on-...) to ensure SDD continues to work at peak write and erase speeds. Will need to be reapplied after OS updates.