Solaris

When looking at the mails and comments I get about my ZFS optimization
and my RAID-Greed posts, the same type of questions tend to pop up over and over again. Here's an example from a reader email:

"I was reading about ZFS on your blog and you mention that if I do a 6 drive array for example, and a single RAID-Z the speed of the slowest drive is the maximum I will be able to achieve, now I thought that ZFS would be better in terms of speed. Please let me know if there is a newer ZFS version that improved this or if it does not apply anymore."

This is just an example, but the basic theme is the same for much for the reactions I see: Many people think that RAID-Z will give them always good performance and are surprised that it doesn't, thinking it's a software, an OpenSolaris or a ZFS issue.

In reality, it's just pure logic and physics, and to understand that we should look a little closer at what vdevs are in ZFS and how they work.

A few weeks ago, we discussed using DTrace for automatically updating media servers when you upload new content.

Yesterday though, I discovered that my D script didn't work any more. I uploaded new songs to my home server, and expected the music daemon to re-scan the music directory, but nothing happened.

That teached me an important lesson about DTrace, and here's what I learned:

This is a long article, but I hope you'll still find it interesting to read. Let me know if you want me to break down future long articles into multiple parts instead.

One of the most frequently asked questions around ZFS is: "How can I improve ZFS performance?".

This is not to say that ZFS performance would be bad. ZFS can be a very fast file system. ZFS is mostly self-tuning and the inherent nature of the algorithms behind ZFS help you reach better performance than most RAID-controllers and RAID-boxes - but without the expensive "controller" part.

Most of the ZFS performance problems that I see are rooted in incorrect assumptions about the hardware, or just unrealistic expectations of the laws of physics.

So let's look at ten ways to easily improve ZFS performance that everyone can implement without being a ZFS expert.

During OSDevCon 2009 in Dresden, I had the honor to present on some lessons learned while putting together a ZFS Automatic-Scrubbing SMF service.

Today, Deirdre was so kind to publish the video recording of my presentation on The Oracle Solaris Video Blog.

From the description:

This talk walks you through the implementation of a simple SMF service. What sounds "simple" at first, develops a life of its own when you consider installation/de-installation, security considerations, error handling and debugging, and of course unexpected little bugs and shortcomings. Finally, we add a GUI to our service by discovering the OpenSolaris Visual Panels project. This "lessons learned" talk is intended to be a practical roundup of things to consider for developers interested in integrating with SMF.

Since November 1st, 2009, when ZFS Deduplication was integrated into OpenSolaris, a lot has happened: We learned how it worked, people got to play with it, used it in production and it became part of the Oracle Sun Storage 7000 Unified Storage System.

Here's everything you need to know about ZFS Deduplication and a few links to help you dig deeper into the subject:

Firefox 3.6 has introduced a new feature (that was in Beta for some time): Personas.

What's a Persona? From Firefox' own description: Personas are easy-to-use themes that let you personalize the look of your Firefox There's a very nicely done video on the Firefox Personas site to introduce the feature.

If you (or your friendly sysadmin) haven't upgraded to Firefox 3.6 yet, you can still install the Personas Plus Add-On to enjoy all of the Personas goodness.