What are distributed systems? - Quazi Nafiul Islam¶

Tags: python, pun

(One of the talks at the 22 June 2016 Amsterdam Python meetup)

Distributed systems?

• Distributed computation (like hadoop, mapreduce).

• Distributed storage (like cassandra, riak).

• Distributed messaging (like kafka).

You need distributed systems if you want to do more than is regulary possible.

With many systems you need things like synchronisation (for instance NTP, network time protocol).

A distributed system is a bunch of computers working together. Such systems have challenges and limitations. Take for instance the CAP theorem for distributed storage systems. You can’t have all three of the following three at the same time:

• Consistency.

• Availability.

• Partition tolerance.

You can for instance value availability over consistency. You give the answer as soon as possible, even if you’re not completely sure you have the full answer (as other nodes might have extra/newer information).