Month: January 2010

Wednesday is the first day of Linux.conf.au proper. I thought that today I’d just keep my notes in a blog post to prevent doubling up.

The keynote was Benjamin Mako Hill talked about various things the most interesting bit was “antifeatures”. Things like DRM, crippling of products etc. The one of these I most hate right now is they way that cheap netbooks have fairly low specs (small resolutions, low RAM, slow CPUs ) partially because they have to keep the spec below a certain value in order to qualify for the really cheap Windows license.

The dreamwidth talk was quiet interesting (although the speakers pre-rehearsed banter between the speakers didn’t really work). Lots of practical examples , war stories and good sound advice.

Selena Deckelmann talked about choosing which open source database your should choose. The quick answer is “what problem are your trying to solve?”. She did a survey of the 50-odd databases out there and got 25 replies. Also did her own research and comparisons. Classified DBs into several categories (which I won’t list) such as

• General Model – Key-Value, OLTP.
• Distribution model (replication, partitioning, sharing).
• Memory vs disk (eg keegin g everything in memory only like memcached).
• HA options, Node failover.
• Code dev model – Core +modules , Monolithic , Infrastructure
• Community dev model – Dictator, Feature driven, Small group, A mix

Results at http://ossdbsurvey.org

• Databases implement each others protocols
• Need verification that protocols correctly implimented
• Need tools/test to check things like replication working
• More connections between projects/people (eg java seperate)

Ted Ts’o – Production-Ready filesystems

• Hard to make robust. Many different workloads, lots of state, very parallel
• Hard to balance getting it out with getting it stable enough to be fairly safe to use
• 75-100 persons-years for filesystem to be production ready.
• eg zfs around a dozen people , start 2001, announced 2005, shipped 2006, people confident with it around 2008-2009
• Ext4 renamed from ext4dev at end 2008
• Ext4 Shipping is some community distributions, soon in some enterprise distributions, widespread adoption 12+ months later
• Lots of bugfixes still in ext4, most not real-world and picked up by auto-tools or careful checks in weird conditions.
• Ted: “my other prefered term for Dbench is ‘random number generator’ “
• Paths like online resize, online defrag that are not regularly tested by users or testers so source of many bugs.
• Many bugs were in the recently subsystems and features
• Making General purpose file system takes longer and a lot more effort than you might expect. Labour of love, hard to justify from business perspective.
• Solid state drives with “flash translation layer” in place are fairly much the same as spinning disks. Extra optimizations for disks don’t help but they don’t hurt

Matthew Garrett on the Linux community

• Started by listing things he’s not talked about
• The Linux community is “Like the Koreas”
• To be a member of the Linux community “you just have to care, just have to turn”
• As community we are very hostile, it’s seen okay to flame and it is being rewarded still
• Should we stop just cause it’s a nice thing to do or because it’ll stop scaring people off?
• Ubuntu code of conduct has mean’t that users are consider part of the community more than in other distributions
• Code of Conduct must be enforced or it’s useless
• “We value code above all else… not a good thing” . We need people to feel that by using software they are part of something
• Communty entirely based on technical excellence or encompasing everybody who users, cares, contributes to projects
• Idea for positive examples Wiki with pointers to COPs and best practice examples
• Not gained behavior standards normally associated with grown communities

Sage Weil – ceph distributed file system

• How different
• scaleable to 1000s , grow from a few
• reliable, HA, replicated data, fast recovery
• snapshots, quota-like accounting
• Motivation – avoid bottlenecks and symetrical shared disks
• avoid manual workload partition, p3p-like protocols, intell storage agents
• POSIX file system , scaleable metadata server
• metadata (MDS) servers/clusters and object store boxes seperate
• CRUSH hash function used to distrubtute objects across devices, works as devices are added. Spread them out explicitly across infrastructure if required
• fast (no lookups), relieable, stable
• celp object storage daemon on each node
• talks to peers on other node: rep data, detect failures, migrate data
• hashing fuction means nodes don’t have to negotiate with each other, CRUSH says where data is going.
• monitor storage nodes, moves data around, make sure it’s in the right places, uptodate. fixes if required.
• raw storage API if you don’t need full filesystem fun (dirs etc)
• proxy that emulates s3 REST interface
• metadata cluster , uses object store for all long term storage, needs memory and fast network for performance.
• metadata streamed to journal. large journal (100s MB) flushed now and then
• snapshotting on per-directory basisi via simple mkdir
• snapshot leverages btrfs copy-on-write storage layer
• file systems client near-posix
• kernel client, FUSE, Hadoop clients
• stable but not production ready
• client should be in mainline kernel soon
• aim to work in multiple datacentre, across unrelieble links
• http://ceph.newdream.net/

Paul Fenwick – Worlds Worst Inventions

Not really a technical talk. More a few stories about funny inventions. Quiet amusing but I’m not sure it fits in with the rest of the conference.

First real day of Linux.conf.au is always full on anticipation. I woke up a little early and nibbled a small breakfast as I walked from ustay to the venue. After the crap weather on the weekend things were stating to look a bit better.

The signup are at the venue was fairly quite with people being processed quickly and many having been signed up for the weekend.

First up was the Welcome talk which had a few hitches. Due to illness it was being given by and understudy who was a little unpracticed with the delivery and had a problem when the overhead screen went blank for 5 minutes due to technical problems (not sure if it was the screen or the laptop’s fault). Highlights were a 42-below ad for Wellington and everyby singing Happy Birthday to Rusty.

I spent the first couple of sessions at the Haechsen/LinuxChix Miniconf since most of the topics were interesting and for various reasons (mumble mumble) talk times between miniconfs were not sync’d so it was hard to move between them.

It looks like this year the video situation is fairly good. All Miniconfs and main sessions are both being streamed live (although in wma format which caused some comment ) and being record for later download. Hopefully It’ll all work out.

Talks I attended:

• Version control for mere mortals by Emma Jane Hogbin was a good intro to VCS and practices including a bit aimed at sysadmins and content maintainers rather than just coders. She obviously likes Bazaar a lot more than git. Goods intro and once again I feel guilty about not using it more.
• Happy Hackers == Happy Code by Sara Falamaki was an overview of what makes programmers happy. Mostly concentrating on tools but with some other bits and pieces mentioned. Great, especially the bit where Sara started throwing (often wildly) lollies to members of the audience who made good suggestions.
• Through the Looking Glass by Elizabeth Garbee gave here perspective on using open source software and the high-school level. Interesting stuff on tools, and how other teens viewed open source and programming and the scary story about how her school had a rule that any student how bought a computer to school running Linux/Unix would be expelled!
• Creating Beautiful Documentation from Lana Brindley covered some high level bits of the process redhat uses to create documentation as well as a bit of an overview of what technical writers do and why their jobs rock 🙂
• Getting you feet wet for Angela Byron gave ways and advice for getting involved with Open source projects ( including the old “woman’s work” (my, not her term)) of documentation etc. Pretty good.

• Code of our own from Liz Henry was about the first feminist orientation talk of the day. Lots of stories and advice for women in open source as well as a few bits where she gave your low opinion of how well some ideas have worked in practice.

Overall fairly interesting sessions. I noticed that for most of the 2 session the majority of people in the room were male and quite a few of the audience questions/comments were from them. This didn’t really cause a problem for most talks which were on general topics but I noticed the “male perspective” was less useful/welcome for Liz Henry’s talk.

For Lunch I wandered around a little bit an eventually found a place called “The coffee club” where I had a soy milkshake and a pesto bruschetta. Very nice.

For the last session I went to “The business of Open Source” Miniconf and then “Libra Graphics”

• The 100 mile Client Roster from Emma Jane Hogbin was an interesting overview of the way her business and business model has evolved and where she thinks the next step is. Good talk and delivery although it’s a bit outside my area for me to give a good review of the content.
• Building a service business using open source software by Cameron Beattie didn’t really appear to me. The talk was a bit flat and delivery lacked much spark.
• Cheap Gimmicks to Make your designs ‘New’ by Andy Fitzsimon from suffered a bit from technical problems with delivery but looked like there was a good talk in there somewhere that just required a bit more prep.
• Dynamic PDF reports via XSL and Inkscape by Peter Lieverdink was cool but a little over my head.
• Inkscape: My Cheerleading Adventures by Donna Benjamin was a little sparse even for a 5 minutes talk

After the end of the day I went along to a Wikipedia Meetup at the Southern Cross Hotel. The Meetup was fairly small ( just 3 other people) but interesting people and several hours of discussion. Some talk about a NZ Wikimedia Chapter and also helping with the Wikimedia stand at the LCA open day.

Last up I grabbed a coffee and cake at Midnight Espresso.

Overall not a bad day, tomorrow will by Sysadmin Miniconf all day wih the Speakers Dinner in the evening.