Adam Leventhal's blog

Month: November 2010

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 variety of roles, joining the ZFS team in 2006 (just as I was leaving to help start Fishworks).

George and Matt bring an amazing knowledge of ZFS — the lower, and upper halves respectively — and are also just great engineers who are already contributing tangibly to the the success of Delphix. You can take a look at Matt’s old blog, or watch George in a bunch of videos (including one of him being interviewed by a muppet).

Welcome to Jed Yueh, our CEO at Delphix, who recently posted his first blog entry.

With three clicks from our intuitive, consumer-grade interface, you can cut through a decade of frustration and redundancy in enterprise datacenters. And customers are quickly seeing the value of the gun vs. the sword: in our first two quarters of sales alone, we added Fortune 1000 customers across several industries, including financial services, telecommunications, high technology, retail, manufacturing, travel, consumer goods, and SaaS.

Stay tuned to the Delphix blog for more on what we’re up to.

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 ZFS dataset, writes are almost 100% sequential, but with activity to multiple datasets, writes become significantly more non-sequential. The ZIL was initially designed to accelerate performance with a dedicated hard drive, but the Hybrid Storage Pool found a significantly better ZIL device in write-optimized, flash SSDs.

In the 7000 series, the performance of these SSDs — called Logzillas — aren’t particularly sensitive to random write patters. Less sophisticated, cheaper SSDs are more significantly impacted by randomness in that both performance and longevity can suffer.

Chris concludes that NV-DRAM is better suited than flash for the ZIL (Oracle’s Logzilla built by STEC actually contains a large amount of NV-DRAM). I completely agree; further, if HDDs and commodity SSDs continue to be target ZIL devices, ZFS could and should do more to ensure that writes are sequential.

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 of the history of RAID-Z, the strengths and weaknesses that have emerged, and a look towards the challenges ahead for ZFS and RAID with some possible solutions and mitigating factors. Thanks to Nexenta for putting the conference together; questions or comments are very welcome.

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