What is a replicated filesystem?
A replicated filesystem is one that stores data across multiple storage devices. Some replicated filesystem designs work at the block level, some at the file level, and some use a hybrid of both concepts.
DRBD is an exa…

This was originally a response on Quora, but it ended up attached to a comment that got downvoted (not by me) and that makes it hard to find so I figured I’d give it some more exposure here. I’ll add some more Gluster-specific commentary at the end, but first I just have to re-use the […]

All good sysadmins know about using tail -f to follow a log file. I use this all the time to follow /var/log/messages and my gluster logs in particular. Maybe everyone already knows this, but it deserves a PSA: after a … Continue reading →

What happens when you press “go” ? We think in abstractions… we code in mega-abstractions… but…I recently read about Amdahl’s law in this awesome article about caching for high performance web sites: http://architects.dzone.com/articles…

In a distributed hash table lookup, like that used by GlusterFS, misses are expensive. Let’s look at how it works and why misses are “bad”.
How DHT works
When you open() a file, the distribute translator is giving one piece of information to find your …

The Cascadia IT Conference is looking for sponsors and proposals for talks, tutorials and panels.

Lets get this thing started! Cascadia IT Conference 2013 is March 15,16. Submit your proposals now. Earlier is better casitconf.org/casitconf13/cf&hellip…

Several of us had a discussion on IRC about the almost-a-year-old GlusterFS quorum enforcement feature, and what quorum enforcement is likely to look like in the future. I tried to explain briefly some plans that had previously been discussed in email among some of the developers, but hadn’t circulated beyond there, and then I realized […]

In addition to watching the election coverage last night, I spent some time giving MooseFS another try. It’s a project I had high hopes for once, I even considered it as an alternative to GlusterFS as a basis for what was then CloudFS, but I was put off by several things – single metadata server, […]

If you’re in the Seattle area and would like to meet up and hear me talk about GlusterFS, come to the Seattle Area System Administrator’s Guild meeting 7:00pm November 8th at the University of Washington (Bldg EE1, Rm 403). There will be dinner sponsor…

One of the most important aspects of disk performance is the difference between seek latency and rotational latency. To put it simply, the time it takes to seek between tracks is at least an order of magnitude greater than the time it takes for the disk to spin – and that’s already more orders of […]

GlusterFS is a distributed file system implemented in user space. It is strictly not a native file system in itself but is an aggregator of different file systems. GlusterFS can aggregate individual file system mount points or directories (called bricks in gluster terminology) to provide a single unified file system namespace. In addition to NFS […]

There are no shortage of ways to look at individual changes to individual lines in a Git repository.  But what happens if you want to see what an entire file looked like, as of a particularly “long time ago”, in the absence of an exact commit mess…

I’m happy to announce the availability of UFO Pilot, an HTML5 web app for accessing a Gluster UFO/OpenStack Swift object store from your Android or iOS mobile device.

Feel free to download it from Github and offer your feedback.
As an aside, Gluster …

One of the “fun” things about consistent hashing in an actual filesystem, as opposed to an object or key/value store, is that you have to support rename operations. Supporting all of the required POSIX semantics around rename can introduce many kinds of complexity, which I’ll probably write about some time, but right now I’ll just […]

Pure functional programming is at the heart of scalable software design… Even when your not using a functional language.  If you’ve ever wondered why “learning a functional language might make you a better developer”, then this post is for you. …

Last month, I received two new servers to replace two of our three (replica 3) GlusterFS servers. My first inclination was to just down the server, move the hard drives into the new server, re-install the OS (moving from 32 bit to 64 bit), and voila, d…

Greetings, If you’ve been trying to access the download server, I’m afraid it continues to be offline. We will try to have a replacement up and running by tomorrow. In the meantime, you can still access release tarballs via bits.gluster.com or from our GitHub repo. And before anyone asks: no, this was not a filesystem …Read more

One of the most common knocks against GlusterFS is that it eats too many CPU cycles. For example: Really not liking GlusterFS now. Performance is quite poor and CPU usage way too high for what it does. I’ve talked about performance issues and expectations many times. With regard to CPU usage, I can’t resist saying […]

A little while back, I tested out the Unified File and Object feature in Gluster 3.3, which taps OpenStack’s Swift component to handle the object half of the file and object combo. It took me kind of a long time to get it all running, so I was pleased to find this blog post promising a […]

This has come up several times in the last week. “I have 2n servers with 2 or 4 bricks each and I want to add 1 more server. How do I ensure the new server isn’t a replica of itself?”
This isn’t a simple thing to do. When you add bricks, replicas are a…