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: , , , , , , , , ,

Another reason Apple misses ZFS

Apple recently announced a new iMac model — in itself, only as notable as the seasons — but with an interesting option: users can choose to have both an HDD and an SSD. Their use of these two is absolutely pedestrian, as noted on the Apple store: If you configure your iMac with both the [...]





Posted on May 20, 2011 at 8:02 am by ahl · Permalink · 5 Comments
In: ZFS · Tagged with: , , ,

Delphix welcomes Matt Ahrens and George Wilson

This week it was my pleasure to welcome my former Sun colleague Matt Ahrens and George Wilson to Delphix. Matt and I studied computer science together at Brown and then joined Sun in 2001. Matt joined Jeff Bonwick to start ZFS while I worked on DTrace. George joined Sun in 1996, and worked in a [...]





Posted on November 19, 2010 at 4:36 pm by ahl · Permalink · Comments Closed
In: Delphix · Tagged with: , , ,

ZIL analysis from Chris George

Chris George from DDRdrive put together a great presentation at the OpenStorage summit looking at the ZFS intent log (ZIL), and how their product is particularly well-suited as a ZIL device. Chris did a particularly interesting analysis of the I/O pattern ZFS generates to ZIL devices (using DTrace of course). With writes to a single [...]





Posted on November 15, 2010 at 2:48 am by ahl · Permalink · Comments Closed
In: ZFS · Tagged with: , , , , ,

RAID-Z at the OpenStorage Summit

I had the chance to speak at the OpenStorage Summit a couple of weeks ago about RAID-Z (the ZFS implementation of RAID). The talk was an accumulation of blog posts and articles written by me and others as well as quite a bit of new material that’s been building up. The talk was an overview [...]





Posted on November 10, 2010 at 8:28 pm by ahl · Permalink · Comments Closed
In: ZFS · 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: , , , , , ,

What is RAID-Z?

The mission of ZFS was to simplify storage and to construct an enterprise level of quality from volume components by building smarter software — indeed that notion is at the heart of the 7000 series. An important piece of that puzzle was eliminating the expensive RAID card used in traditional storage and replacing it with [...]





Posted on July 21, 2010 at 11:46 pm by ahl · Permalink · 8 Comments
In: ZFS · Tagged with: , , , , ,

A Logzilla for your ZFS box

A key component of the ZFS Hybrid Storage Pool is Logzilla, a very fast device to accelerate synchronous writes. This component hides the write latency of disks to enable the use of economical, high-capacity drives. In the Sun Storage 7000 series, we use some very fast SAS and SATA SSDs from STEC as our Logzilla [...]





Posted on July 19, 2010 at 11:29 pm by ahl · Permalink · Comments Closed
In: ZFS · Tagged with: , , ,

Triple-Parity RAID-Z

Double-parity RAID, or RAID-6, is the de facto industry standard for storage; when I started talking about triple-parity RAID for ZFS earlier this year, the need wasn’t always immediately obvious. Double-parity RAID, of course, provides protection from up to two failures (data corruption or the whole drive) within a RAID stripe. The necessity of triple-parity [...]





Posted on July 21, 2009 at 11:48 pm by ahl · Permalink · 14 Comments
In: ZFS · 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: , , ,