Strategy for storage on Mac Pro with SSD

I have been building out Mac Pros for a while with SSD for the boot, user accounts and all the apps that fit.

Placing the large user data that doesn't fit as well as large Apps on the magnetic storage has worked well as the system and user caches stay on the SSD. You absolutely want your code and build scratch / temp files / object files on SSD for speed reasons.

The simpler the better - I have been using software RAID to span the HDD so the users all see three volumes whether or not they have one drive partitioned, a mix of SSD/HDD or full SSD/HDD and external drives for data and/or TimeMachine.

Macintosh HD - SSD unless lower performance is OK. Data - all the HDD striped (optional on non SSD macs) Time Machine - internal if possible - external

On the fastest macs - we are thinking of striping 3 SSD as DATA - moving the Time Machine to external storage as buying large (teraByte) SSD is still a costly proposition.

One recommendation is to actually monitor disk usage. Similar to the adage in software development that says instead of trying to guess how to improve performance, run a profiler that will tell you what parts of the software get used the most and could be improved.

While you could use the Activity Monitor that has some per-process information, better information can be found via the command line with sudo fs_usage -f filesys.

Since you are fairly sure the system will reside on the SSD, I wouldn't try to monitor the bootup phase. Start the above command as early as possible and then try to do a normal workflow. Output includes a path name for each file accessed. Analyze results to see what files are actually being accessed the most and go from there.