https://medium.com/xandr-tech/2013-09-17-outage-postmortem-586b19ae4307 → https://web.archive.org/web/20250505112812/https://medium.com/xandr-tech/2013-09-17-outage-postmortem-586b19ae4307 (#251)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

README.md

@@ -186,7 +186,7 @@
 
 [Amazon](https://aws.amazon.com/message/12721/). At 7:30 AM PST, an automated activity to scale capacity of one of the AWS services hosted in the main AWS network triggered an unexpected behavior from a large number of clients inside the internal network. This resulted in a large surge of connection activity that overwhelmed the networking devices between the internal network and the main AWS network, resulting in delays for communication between these networks. These delays increased latency and errors for services communicating between these networks, resulting in even more connection attempts and retries. This led to persistent congestion and performance issues on the devices connecting the two networks.
 
-[AppNexus](https://medium.com/xandr-tech/2013-09-17-outage-postmortem-586b19ae4307). A double free revealed by a database update caused all "impression bus" servers to crash simultaneously. This wasn't caught in staging and made it into production because a time delay is required to trigger the bug, and the staging period didn't have a built-in delay.
+[AppNexus](https://web.archive.org/web/20250505112812/https://medium.com/xandr-tech/2013-09-17-outage-postmortem-586b19ae4307). A double free revealed by a database update caused all "impression bus" servers to crash simultaneously. This wasn't caught in staging and made it into production because a time delay is required to trigger the bug, and the staging period didn't have a built-in delay.
 
 [AT&T](https://users.csc.calpoly.edu/~jdalbey/SWE/Papers/att_collapse.html). A bad line of C code introduced a race hazard which in due course collapsed the phone network. After a planned outage, the quickfire resumption messages triggered the race,  causing more reboots which retriggered the problem. "The problem repeated iteratively throughout the 114 switches in the network, blocking over 50 million calls in the nine hours it took to stabilize the system." From 1990.