It helped that the SoftLayer servers (mostly SuperMicro, although some Lenovo post IBM acquisition) …

… It helped that the SoftLayer servers (mostly SuperMicro, although some Lenovo post IBM acquisition) were very stable. This fed into the stability of FreeBSD and the operability of Erlang. Whenever we shut down chat servers, we'd find some clients with chat connections open for 45 days (mostly Nokia S60, which had a stable networking stack, but no push services, so we had to stay connected). Ocassionally, we'd need to do BEAM updates or FreeBSD kernel updates to address issues, but mostly servers were running for months or years uninterrupted. This is only possible with quality software and hardware. Both FreeBSD and BEAM/Erlang/OTP are quite approachable for local patching as well. They don't have a lot of churn, so patches don't need a lot of changes between releases, and things are well organized. We didn't have a ton of patches, but we did run things towards the limits. Not quite the same limits that Netflix explores though. …