Viewing profile — theojulienne

They were originally on their own datacenters + huge amounts of burst and ancillary stuff in AWS, the internal push to move away from "the competitor's cloud" after the acquisition…

I think people spend way too much time trying to say that LLMs are bad / shouldn't be used / etc because the LLM can't get it right the first time and/or makes mistakes. I think th…

This. A ~staff software engineer designing big changes at one level above the raw implementation details using Opus 4.7 + superpowers today can genuinely ship multiple times more a…

I used to be a hubber - I really hope that institutional change happens at GitHub and I'm glad there are people there still fighting for it. I left because caring deeply (maybe, li…

I can't speak to the last few years since I left, but over the many years I was there the git storage layer was almost never the core issue - it was well designed by infrastructure…

Thanks for the suggestion! I did come across the `tcpsynbl.bt` script as I was writing up this post, but wanted to add the additional information around namespaces and report addit…

We didn't find any metric that surfaced zombie cgroups, presumably because the kernel mostly tries to hide them from user space since they have been deleted, but haven't been clean…

This insert_failed issue described in the video was one of the ones we discovered during investigations as well, but it was already well understood because of this excellent Xing b…

This is actually interesting, we chose to use an overlay network because Kubernetes was a new, complex system that we initially didn't have experience with internally, and so we wa…

The bcc script was run on the Kubernetes node itself directly over SSH, but it should be possible to run it in a privileged container as well.

This is a great question, thank you for asking! Initially a few teams around the org had folks investigating poor performance from different perspectives of the applications that w…

Fastly's MAC-based solution to this was actually one of the existing implementations we read about back when designing the original implementation of GLB in 2015/16, along with Fac…

We found that we could achieve 10G line rate with just the queues available to the VF, the NIC didn't seem to be a bottleneck providing DPDK was processing packets faster than line…

During some analysis we did notice that at least some cloud providers default to having instances with public IPs (with no network-level ACLs) by default, and some Linux distributi…

Since SYN packets only contain a limited set of information, if the SYN packets have spoofed source addresses then it is very difficult for a device in the destination network to f…

For the most part, since synsanity is a subset of SYNPROXY, the performance benchmarks from this SYNPROXY slide deck (and other documentations) are still relevant: http://people.ne…

Great question! A large portion of our infrastructure still runs on Ubuntu Precise, and so the default "supported" options for the kernel on those machines are 3.2 or 3.13. Once yo…