Blog Posts

Ever since Oracle announced that they’ll buy Sun (no link, page no longer exists), there has been a lot of discussion about the future (some would say “fate”) of OpenSolaris in the “community”.

In fact, the last 15 months have been very instructive in terms of how communities work, or how they don’t.

Let’s check out what a community is supposed to do, and what it is not supposed to do, in the light of the latest OpenSolaris announcement: Illumos.

Every year, on the last Friday of July, Sysadmin Day is celebrated around the world.

You know, the guy (or gal) that makes sure you always receive your emails on time, strips away the spam, cuddles your web server so you can write blog articles, or makes sure the network is always online, so you can read your favorite blogs. Or install new servers and storage so your web experience becomes faster and so your data is never lost.

Sysadmins often have a hard time: Noone calls them to tell them “Thank you for delivering all my emails!” or “Thanks for making sure my data is backed up every day!”. Instead, they only get phonecalls when something goes wrong, or worse yet, some anonymous electronic complaint in some soulless ticketing system.

Therefore, this Friday, the 30th of July, 2010, think about your sysadmin, call her up and say something nice, or consider giving them a gift. Here are some geeky gift ideas for sysadmins to celebrate Sysadmin Day 2010, from low-budget to truely-devoted-appreciation pricing order.

After all, you really don’t want your sysadmin to turn into a grumpy BOFH, do you?

When talking to customers, partners and colleagues about Oracle Solaris ZFS performance, one topic almost always seems to pop up: Synchronous writes and the ZIL.

In fact, most ZFS performance problems I see are related to synchronous writes, how they are handled by ZFS through the ZIL and how they impact IOPS load on the pool’s disks.

Many people blame the ZIL for bad performance, and they even try to turn it off (no link, solarisinternals.com no longer exists), but that’s not good. Actually, the opposite is true: The ZIL is there to help you.

In this article, we’ll learn what synchronous writes are, how they’re processed by ZFS, what the ZIL is, how it works, how to measure ZIL activity and how to accelerate synchronous write performance, which is at the root of many, if not the majority of ZFS performance problems.

Darren from ProBlogger today posted his 7 Link Challenge. A fun idea in which he asks bloggers to share 7 links to posts, based on the 7 criteria he selected.

ProBlogger is a great website with lots of useful tips for bloggers. Even if you don’t plan to make money with your blog, or if you don’t think of yourself as a pro blogger, this site is still one of the best in terms of blogging advice.

I’m currently reading his book “ProBlogger” (affiliate link) and I can highly recommend it to anyone who is thinking more seriously about blogging.

Now, let’s get started with the ProBlogger 7 Link Challenge for Constant Thinking:

One of the best information sources for any topic are blogs, and the Oracle Solaris operating system in all its variants (Solaris 10 and OpenSolaris) is no exception. Most of what I learned about OpenSolaris was through blogs, or through interacting with Solaris bloggers.

As a way of saying “Thank You”, I did some research and came up with a list of the top ten Solaris related blogs with the highest traffic on the Internet.

But first, let’s clear up some basic rules.

The developers of ZFS are a funny bunch of people. You can tell that by watching the “ZFS: The Next Word” talk, meeting them on conferences, reading their blogs or their comments on mailing lists.

And there are also some funny parts in the ZFS source code, too. In fact, if you use ZFS, you’ll have a funny joke sitting on your disk, right under your nose!

I was reminded about this particular joke while listening to Ulrich Gräf’s excellent talk on ZFS internal data structures during OSDevCon 2009 (no link, osdevcon.org no longer exists) (watch a video of Ulrich’s talk here (no link, sun.com no longer exists)).

But first, we need to dig a little bit into the world of ZFS data structures.

War is waging in the galaxy. This time it’s not the Rebels against the Empire, or Good vs. Evil.

No, this war is different, and it has been going on ever since products designs companies entities existed.

What I mean is the war between Quality and Popularity.

Let me explain:

(Drumroll, Roman fanfare, then dramatic Anime action trailer a la Mortal Kombat, etc.)

As of May 21st, Google officially declared war on the Apple iPhone.

Sure, there was some teasing here and there for weeks, if not months, but this is serious.

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.

One of the web 2.0 startup hypes du jour is called Flattr. It’s a micro-payment service that enables readers to allocate a monthly budget they can use to “flattr” blog posts and other content by clicking a simple badge. The monthly flat-rate is then distributed to the “flattred” authors as a way of appreciation.

More on that in this short video.

A lot of people are jumping on the Flattr bandwagon, and of course, rewarding creators is always goodness.

But I’m not convinced.

Why? Because IMHO there’s no need for a middle man handling the “Thank You” transaction between a blogger (or other content creator) and the reader (or other content consumer).

Instead, here are ten (10) better ways to accomplish the same thing (supporting your favorite creator). They can involve money or not - you choose - and in each of them, everybody wins.

In the last couple of posts, we used DTrace to notify our media servers and perfected our script a bit.

But the script is still not ready to be used on our home servers yet: It requires manual start and stop, not quite the service oriented automatism we’re used to in the Oracle Solaris world.

The next step is to wrap our DTrace script inside a Service Management Facility (SMF) service, then wrap everything into a shell script that will easily install or remove the service whenever we need it.

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 (no link, osdevcon.org no longer exists), 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 (no link, sun.com no longer exists).

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.

Before we continue with our Home Server Scripting Series, let’s throw in a simple but useful DTrace hack.

One of the most typical uses for a home server is to serve music or videos to home entertainment equipment. In my case, I’m using the Firefly Media Server (no link, fireflymediaserver.org no longer exists) to serve music to my Roku Soundbridge and Mediatomb (no link, page no longer exists) for videos.

The Media Server Update Problem

Whenever I upload new music or videos to my OpenSolaris home server (typically by rsync-ing my laptop home directory), both Firefly and Mediatomb need to be restarted so they detect that new files are sitting in their directories, waiting to be served.

When I blogged about my OpenSolaris Home Server a while ago (no link, sun.com no longer exists), little did I know that this would become my most popular entry in my old blog!

In fact, R.G. (no link, page no longer exists) was so kind to call my setup “perilously close to being an AMD reference design (no link, opensolaris.org no longer exists)”. Thanks, R.G.! Read about his final setup here (no link, opensolaris.org no longer exists). And BTW, if you’re into e-guitars, check out his GEOFEX page, a great resource for guitar effects.

So let’s review our reference design and discuss some modifications to better suit your needs:

Yesterday, I cleaned up my home directory at work. I went from ca. 15 GB of data down to 1.1 GB. And I only stopped there, because I didn’t want to spend too much more time cleaning up. Here’s how to do it.

In the previous post of this mini-series, we looked at why it’s important to have our emails and files organized, then attacked our INBOX to reach zero-message-nirvana. I’m happy to see that others are living by these principles, too. Thanks, Gregor!

Now let’s look at that other dark spot in our IT lives: Our Desktop and file system. If you’re like me, you see this very often, too: Cluttered desktops with so many files and folders and downloads and icons and stuff, you can barely make out the underlying desktop background.

Spring’s around the corner and the Easter weekend is upon us, giving us some time to sit back, relax and do some spring cleaning!

This also applies to your data, in particular your Email folders and your home directories. In this two-part series, we’ll clean up our email INBOX to zero (yes: null, nada, zip) emails, simplify email folders, then clean up our home directory file structure. That’ll save us time, help us find peace of mind and make us more efficient so we can concentrate our energies on what really matters to us.

OpenSolaris OS comes with the Image Packaging System (IPS) (no link, opensolaris.org no longer exists) for managing installation and additional software. By default, it is configured to pull packages from the /release (no link, opensolaris.org no longer exists) repository, but of course there are many other interesting repositories with software to install from.

Chris Gerhard recommends adding at least the /extras repository (free, registration required (no link, sun.com no longer exists)) so you can easily install VirtualBox, Adobe Flash, TrueType Fonts etc.

If you have a support contract or are an Oracle/Sun employee, you may want to switch your preferred repository to the supported one. The more adventurous may want to switch to the development repository (no link, opensolaris.org no longer exists).

Then, the Software Porting Community on OpenSolaris.org (no link, opensolaris.org no longer exists) has a hierarchical system for making open source software available on OpenSolaris through two repositories: /pending and /contrib.

And then there are a couple of more repositories from user groups, private people, companies offering commercial packages and so on.

One way to register package repositories with the IPS on your home server is by using the package management GUI, or by using the pkg(1) (no link, opensolaris.org no longer exists) command (See also: “How to Add or Update a Publisher (no link, sun.com no longer exists)”).

But of course we want to stick to our “Script Everything” philosophy and write ourselves a small script that takes care of all of our package configuration needs.

Since November 1st, 2009, when ZFS Deduplication was integrated into OpenSolaris (no link, genunix.org no longer exists), 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 (no link, sun.com no longer exists).

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

Last week, we looked at how essential scripting is for administering home servers (one of the 7 tips for home server bliss) and we wrote us a little script for enabling automatic snapshots.

Another thing that you’ll almost certainly want to do on your OpenSolaris home server is enabling power management. This will ensure your server spends as little power as possible when idle, while still being powerful when needed.