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Archive for the ‘systems administration’ Category

Memcached and MySQL – What good is it?

Posted by John Adams on May 17th, 2009

I posted this in response to a post on GigaOM, but it was such a long comment, I felt that it was worthy as a post on it’s own.

The workloads of social networking sites fall mostly into the ‘read lots, write once’ class (most of the web exists within this paradigm.) Regardless of the database [...]

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Velocity Preview

Posted by John Adams on May 7th, 2009

There’s a small interview with me in today’s O’Reilly radar, where I talk about some of the things that I’ll be presenting as part of my Velocity 2009 talk. You can listen to, and read the transcript here:

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Finding usernames through iTunes DAAP

Posted by John Adams on January 13th, 2009

Often on our local network, someone will start using up all of our outbound Internet bandwidth, and this leads to the network administrator’s dilemma:
How do we find the user in question so we can thump them on the head to make them stop?
This is a basic exercise in information gathering. For the most part, [...]

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Netgear fixes WGR3500 bandwidth issues, somewhat.

Posted by John Adams on January 10th, 2009

On this page, Netgear releases Firmware version 1.0.30 for the WNR3500 router. 
In my previous Apple Macbook Pro to Local network host (Mac Mini) testing, my top connection speed was around 2.4 Mbps. After the upgrade, it’s between 4.65Mbps and 7.5Mbps. Nothing near the promised speeds of 802.11N (300Mbit/sec), but I suspect that this is because [...]

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Outgoing blacklists, or, stop the bouncing.

Posted by John Adams on December 12th, 2008

At Twitter, we have many users which sign up for the service and mistype or enter invalid email addresses. Our product group doesn’t want us to use email verification, and for the most part, we cannot because we accept signups via mobile (through the 40404 SMS short-code.) If we bounce too many messages for [...]

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Network performance measurement

Posted by John Adams on November 23rd, 2008

After building a new gigabit network here, we wanted to know exactly what our performance was like. 
I turned to CAIDA, the Cooperative Association for Internet Data Analysis, which has long been a provider of excellent network performance tools. Their research focuses on developing tools to measure the Internet in many amazing ways, such as this map [...]

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Upgrading your home network to Gigabit Ethernet

Posted by John Adams on November 22nd, 2008

This afternoon was a chaotic adventure in upgrading my home network to Gigabit Ethernet. I upgraded my wireless hub from 802.11g to 802.11N, and our internal network from 100mbit to GigE so I can move videos and music around the network faster.
From cabling issues to configuration problems, here’s some tips so that you never have [...]

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ack!

Posted by John Adams on July 17th, 2008

I’ve been experimenting with a few things this week while trying to wade my way through Twitter’s infrastructure. One tool that’s been of extreme help in digging through source code and an extensive set of configuration files has been ack!
It’s the only piece of software I know of that has ‘–thpppt’ as an option (Install [...]

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DNS Patches released today for many platforms

Posted by John Adams on July 8th, 2008

If you’re responsible for DNS at your organization, I urge you to immediately download updates for your DNS servers and patch them, today. Dan Kaminsky and other members of the DNS community announce that they are releasing patches for an extremely serious cache resolver issue impacting many vendors of DNS software, including ISC BIND and [...]

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Day one, Velocity…

Posted by John Adams on June 23rd, 2008

I made it to Velocity around lunch as I was dealing with work business, but so far it’s been pretty decent. Thanks to Jesse Robbins for the invite to speak this evening at Ignite, and for access to the conference.
The day opened (for me, at least) with the Measuring Performance presentation. The general takeaway [...]

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