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Linux Performance
This page links to various Linux performance material I've created, including the tools maps on the right.
linux  sysadmin  tools  monitoring  performance 
november 2017 by ignatz
Heroku finds out that distributed queueing is hard
Stage 3 of the Rap Genius/Heroku blog drama. Summary (as far as I can tell): Heroku gave up on a fully-synchronised load-balancing setup ("intelligent routing"), since it didn't scale, in favour of randomised queue selection; they didn't sufficiently inform their customers, and metrics and docs were not updated to make this change public; the pessimal case became pretty damn pessimal; a customer eventually noticed and complained publicly, creating a public shit-storm.

Comments: 1. this is why you monitor real HTTP request latency (scroll down for crazy graphs!). 2. include 90/99 percentiles to catch the "tail" of poorly-performing requests. 3. Load balancers are hard.

http://aphyr.com/posts/277-timelike-a-network-simulator has more info on the intricacies of distributed load balancing -- worth a read.
heroku  rap-genius  via:hn  networking  distcomp  distributed  load-balancing  ip  queueing  percentiles  monitoring  via:jm 
february 2013 by ignatz
You've Been Left Behind & I Nailed Your Wife | MetaFilter
send email from beyond the Rapture to the lamers who got Left Behind!
religion  ha  christianity  rapture  churchianity  monitoring 
july 2008 by ignatz
GRE PSR-500 Portable Scanning Radio
handheld scanner that does apco p25 and trunking
radio  scanning  apco25  monitoring  ht  p25 
february 2008 by ignatz

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