What's That Noise?! [Ian Kallen's Weblog]

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20071029 Monday October 29, 2007


Every family and every community has them. Addicts. Lives twisted by chemical dependency and the accompanying mental illnesses. Maybe I'll never fully understand how lives can wind down into oblivion in that way, given the many opportunities to I consider myself lucky to have never succumbed to such an existence.

From his sister, here's a short contribution to understanding the life, decline and death of one of my teenage cohorts Sherwood Brewer. For now and evermore, I imagine he's partying with Skitchie: boot-a-doot-doot!


( Oct 29 2007, 08:59:13 AM PDT ) Permalink

20071026 Friday October 26, 2007

memcached hacks

I needed to clear a cache entry from a memcached cluster of 5 instances. Since I didn't know which one the client had put it in, I concocted a command line cache entry purger. netcat AKA nc(1) is my friend.

Let's say the cache key is "shard:7517" and the memcached instances are running on hosts ghcache01, ghcache02, ghcache03, ghcache04 and ghcache05 on port 11111 the incantation to spray them all with a delete command is

$ for i in 1 2 3 4 5
> do echo $i && echo -e "delete shard:7517\r\nquit\r\n" | nc -i1 ghcache0$i 11111
> done
and the output looks like
which indicates that the memcached instance on ghcache02 had the key and deleted it (note the memcached protocol response: DELETED), the rest didn't have it and returned NOT_FOUND.

For more information on the memcached protocol, see the docs under source control.


( Oct 26 2007, 12:29:37 PM PDT ) Permalink

20071014 Sunday October 14, 2007

Benchmarks Smenchmarks

I've been hearing about folks using the LightSpeed web server instead of Apache for its supposed performance gains and ease of use. OK, so maybe if you're not familiar with the subtleties and madness of Apache, it can seem complicated. But the performance issues are often red herrings. Granted, it's been a few years since I've done any web server benchmarking but from my previous experience with these things, the details really matter for the outcomes and in the real world, the outcomes themselves matter very little.

The benchmark results published on the LightSpeed Technologies web site raised a flag for me right away: their comparison to Apache 2.0 was with the pre-forked MPM instead of the worker MPM. Is it any wonder that the results are pretty close to those for Apache 1.3? Either they had no idea what they were doing when they performed this benchmark or they knew exactly what they were doing and were burying the superior scalability of the worker MPM. Pitting a threaded or event driven process model against a forked one is just stupid. However, the evidence leans more towards willful sloppiness or fraud than ignorance. For instance, they claim to have raised the concurrency on Apache above 10k connections ... but they link to an httpd.conf that has MaxClients set to 150. RTFM, that can't happen.

Why don't these things matter in the real world? In benchmark world, there aren't varying client latencies (slow WAN links, etc), varying database response times (for instance MySQL's response times are very spikey), the vagueries of load balancers ebbing and flowing the load and logging configurations aren't set up for log data management. In the real world, application design and these various externalities are the culprits in application performance, not CPU bottlenecks in the web server runtime. The PHP interpreter itself is likely not your bottleneck either. If you're writing crap-assed code that performs unnecessary loops or superfluous database calls, it's going to run like crap no matter what web server is driving it (I've had to pick through a lot of error-ridden PHP code in my day). With Apache's support for sendfile() static file serving and all of the flexibility you get from mod_proxy, mod_rewrite and the rest of the toolkit, I don't understand the appeal of products like LightSpeed's.


( Oct 14 2007, 11:43:08 PM PDT ) Permalink

20071013 Saturday October 13, 2007

When Is A Blog Not A Blog?

The Revolution Will Not Be Televised There are blogs that don't take comments (like this one: I don't have time to moderate spam). There are mainstream media sites that are adopting reader comments. There are blogs being published by independent companies with editorial staff. There are big media organizations publishing columns and event streams as blogs. So I'm finding myself asking some basic questions about blogging of late: Is it an indication of maturation or mutation of the blogosphere that there's quibbling about what's a blog and what isn't? Is main stream media's co-opting of blogospheric mores a harbinger of a thermador to some un-televised revolution? Has the little town become too much of a metropolis that twitter, facebook and other social media are the destinations of urban flight?

The basic existential questions of the blogosphere and where its boundaries reside have been open to consideration (and re-consideration) for quite some time. Not a day goes by on the Technorati support forums without a splogger showing up to complain that their spam isn't getting indexed (Note: I'm not saying everyone who has indexing problems is a spammer, I'm saying spammers come rolling in to complain about it). A few weeks ago, Scoble melodramatically lamented that the TechMeme leaderboard heralds the death of blogging":

I was just looking at the TechMeme Top 100 List and noticed that it has very few bloggers on it. I can only see about 12 real blogs on that list. Blogging being defined as 'single voice of a person.' Most of the things on the list are now done by teams of journalists - that isn't blogging anymore in my book.
It's true, a lot of the many of the successful blogs have a prolific editorial staff. But death? Really? Why is blogging as an individual practice more or less than blogging as part of a collaborative enterprise? The existence of the weblogsincs, gawkers and huffington posts of the world are manifestations of blogging as a format but are from what I can tell are no less or more blogs than any others. New blogs continue to be created every second, and some of them will eventually develop thriving audiences.

The line between micropublishing and macropublishing is blurring. Reuters recently announced they they're taking comments on stories and Ally Insider's revelation that the New York Times is posting reader comments got a lot of play. In his post about Technorati rankings, Doug Karr doesn't feel that CNN Political Ticker should be considered a blog. So I'm asking myself, when is a blog not a blog?

Sometimes blogs (the narrower Scoble definition kind) provide the primary source for the facts of our times. Other times, it's main stream media that is bringing forth those facts. As the emergence of blogs that operate like main stream media continues and main stream media adopts blogging as a technology and practice, perhaps this is the ultimate outcome of a leveled publishing playing field: changes will flow along many vectors, cross bred practices are inevitable and Darwinistic rules will prevail such that a lot of things that you'd previously not have considered blogs are morphing into them.


( Oct 13 2007, 11:22:11 PM PDT ) Permalink