Re:Slack is experiencing a service disruption
by yjftsjthsd-h on Thursday September 30, 2021 @08:58PM
(#28713245)
Is DNS truly so high load that they need substantial caching? I mean, DNS responses should be kilobytes on the high end; it seems like they should barely register on overall traffic.
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Re:Slack is experiencing a service disruption
by CaliforniaKarl on Thursday September 30, 2021 @11:56PM
(#28714311)
Imagine a home with some IoT devices: A smart thermostat, a smart TV, a smart doorbell, and three cameras.
The thermostat connects out every 30 seconds to send a temperature report, and to check for settings changes.
The smart TV, every 30 seconds, sends a compressed snapshot of the image currently being displayed, for ad generation.
The doorbell starts a new connection to stream video whenever movement is detected. The cameras do the same.
Each device was built without any thought to DNS caching. As such, every new connection is going to trigger a new DNS lookup. Multiply that by however many homes are in the area, and the load really starts going up. Especially because each lookup from the device causes a series of lookups to happen on the recursive DNS server.