APFS in Detail: Performance

This series of posts covers APFS, Apple’s new filesystem announced at WWDC 2016. See the first post for the table of contents. Performance APFS claims to be optimized for flash. Flash memory (NAND) is the stuff in your speedy SSD. Apple changed the computing industry when it put flash into the iPod and iPhone, volumes for which [...]





Posted on June 19, 2016 at 7:36 pm by ahl · Permalink · 11 Comments
In: Software · Tagged with: , , , , , ,

On RAID-6 recovery

RAID algorithms have become a particular fascination of mine, and I recently read a very interesting paper that describes an optimization for RAID reconstruction (by Xiang, Xu, Lui, Chang, Pan, and Li). Before writing double- and triple-parity RAID algorithms for ZFS, I spent a fair bit of time researching the subject and have stayed interested [...]





Posted on September 21, 2011 at 10:33 pm by ahl · Permalink · One Comment
In: Software · Tagged with: , , , , ,

Flash news I wish I could read

For a short while, I ran the flash memory strategy at Sun and then Oracle, so I still keep my ear to the ground regarding flash news. That news is often frustratingly light — journalists in the space who are fully capable of providing analysis end up brushing the surface. With a tip of the [...]





Posted on July 1, 2011 at 6:46 pm by ahl · Permalink · 3 Comments
In: Flash · Tagged with: , , , , , , , , ,

Fishworks history of SSDs

This year’s flash memory summit got me thinking about our use of SSDs over the years at Fishworks. The picture of our left is a visual history of SSD evals in rough chronological order from the oldest at the bottom to the newest at the top (including some that have yet to see the light [...]





Posted on August 17, 2010 at 2:25 pm by ahl · Permalink · Comments Closed
In: Fishworks · Tagged with: , , , , , ,

Hybrid Storage Pools in CACM

As I mentioned in my previous post, I wrote an article about the hybrid storage pool (HSP); that article appears in the recently released July issue of Communications of the ACM. You can find it here. In the article, I talk about a novel way of augmenting the traditional storage stack with flash memory as [...]





Posted on July 1, 2008 at 3:49 pm by ahl · Permalink · 2 Comments
In: Fishworks · Tagged with: , , ,