Summary So Far of Apple Fusion Technology — Attempted on MacMini, Mac Pro
Apple Fusion technology = a combination of an SSD and a hard drive into a single desktop volume in which the system migrates frequently used files to the SSD to enhance performance.
Note that I have not tested an official Apple “Fusion” setup. My goal has been to see if a 3rd-party SSD plus Apple HDD can work.
What I’ve found so far:
- Using an OWC 240GB 6G SSD + 1TB hard drive in MacMini, no Fusion “migration” occurs. In short, the Fusion technology does not work with a 3rd party SSD, operating instead as “dumb” JBOD. Apparent reports to the contrary leave me skeptical, or that the model/brand of SSD might matter.
- The “special” version of Disk Utility is indeed a new build (444), complete with a bug that is eager to merge two separate internal drives/volumes in a Mac Mini. To erase or verify or repair internal drives, one will have to obtain a non-special version of Disk Utility (build 430), or use the command line 'diskutil' until this bug is fixed.
- On a Mac Pro running OS X 10.8.2 with either a PCIe SSD or SATA SSD, the Fusion technology does not work, operating as “dumb” JBOD.
Other claims based on 'dd'
My testing shows that using 'dd' is a totally inappropriate way to measure disk I/O speed— Disktester reads the same file ~19 times faster than 'dd' (from the SSD or cache, about ~3.8X faster from the HDD).
MPGmini:test admin$ dd if=blob-0999.blob bs=65536 4096+0 records in 4096+0 records out 268435456 bytes transferred in 9.582504 secs (28013080 bytes/sec) = 26.7 MB/sec MPGmini:test admin$ disktester read-files blob-0999.blob DiskTester 2.2 64-bit, diglloydTools 2.2 fc5, 2012-10-28 13:40 ... Read 1 files totaling 256MB in 0.5 seconds @ 511MB/sec
Furthermore, 'dd' uses the OS X unified buffer cache, so it doesn’t measure disk speed at all if the data is cached.
Hence I dismiss the jollyjinx.tumblr.com 'Fusion' claims in their entirety as unreliable, and an apparent failure in test methodology.