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Test Driven Infrastructure – Validating Layer 1 Networking with Nagios
Previously we’ve talked about how we use Nagios / Icinga for three broad types of monitoring at LMAX Exchange: alerting, metrics, and validation. The difference between our definitions of alerting and validation is a fine one and it more has to do with the impo…
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Leaping Seconds
Just before New Year 2017 a leap second was inserted into Coordinated Universal Time (UTC). At LMAX Exchange we had some luxury to play with how we handled the leap second. January 1st is a public holiday, there’s no trading, so we are free to do recovery if so…
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How computer clocks work and how they are adjusted
A month or two ago I was asked by someone in our Operations team what clock synchronisation is and why we need to do it. I gave them a very basic few sentence answer. That got me thinking that I never read an easy explanation when I myself got started …
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Solving MiFID II Clock Synchronisation with minimum spend (part 7)
In this series we are attempting to solve a clock synchronisation problem to a degree of accuracy in order to satisfy MiFID II regulations, and we’re trying to do it without spending a lot of money.So far we have:
- Talked about the regulations and how we might solve this with Linux software
- Built a “PTP Bridge” with Puppet
- Started recording metrics with collectd and InfluxDB, and
- Finished recording metrics
- Drawn lots of graphs with Grafana and found contention on our firewall
- Tried a dedicated firewall for PTP
Solving MiFID II Clock Synchronisation with minimum spend (part 6)
In this series we are attempting to solve a clock synchronisation problem to a degree of accuracy in order to satisfy MiFID II regulations, and we’re trying to do it without spending a lot of money.So far we have:Talked about the regulations and how …
Setting up my new ASUS UX301LA
I spoilt myself in 2013 for my Birthday and Christmas and bought the beautiful ASUS Zenbook UX301LA. The model I ordered comes with a touch screen WQHD (2560×1440) display, an Intel i7 4558U CPU, 8GiB of RAM and 2 internal SSDs. Needless to say it’s ve…
Diagnosing a Drupal 7 cache generation problem
My company launched their new website recently. When we launched before Christmas we encountered a reoccurring problem that was more difficult than most to diagnose. The problem itself is very specific to our site so I doubt the exact details will help…
Fedora Directory Server and Solaris 10
Now something more meaty: configuring Solaris 10 to use Fedora Directory Server as an LDAP source of users, groups and authentication. This information is sourced from the FDS Project and Sun documentation.In order for PAM authentication to work, the S…
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