tiering

Apple’s Fusion Drive – An SSD Cache for the Macintosh

Apple's Chart of Fusion Drive Performance for the new Mac MiniOn October 23 along with the highly-anticipated announcement of the iPad 4, Apple rolled out new Macintosh computers that for the first time in an Apple product pairs an SSD with a conventional HDD to get the best combination of capacity, speed, and price.  The company calls this its Fusion Drive, not to be confused with Fusion-io’s highly-regarded products.

The SSD Guy did not attend the announcement, and there is little on the Apple website.  I contacted Apple, and they don’t have very much detail to share at this time.  This is important to note, since Continue reading

SSDs and Caching

IBM: Effect of Data Placement on SSD EffectivenessOne of the SSD Guy’s favorite subjects is caching and SSDs.  This is because I wrote a book on processor caches in the early 1990s, and the advent of SSD caches in storage systems hearkens back to the technology detailed in that book.

Caching works well whenever there are two layers in the memory hierarchy since the fast expensive layer can replicate data in the slow inexpensive layer to accelerate the processor’s performance. Continue reading