Tag: distributed systems

The CAP Theorem is probably not for you

The CAP Theorem frequently comes up in conversations around distributed systems and system design. If you’re looking at resources on system design, it will inevitably come up. However, chances are you’re not the target audience for the CAP Theorem and you’re probably better off ignoring it altogether. CAP was presented as a keynote by Eric […]

MongoDB Read Preferences

MongoDB read preferences give you control over read behavior when using replicasets. Writes in every environment go to primary, but reads can be configured to read from secondary or primary based on various criteria. In most versions of mongo, the read preference defaults to primary in the client but you should check your version for […]

Why the words in “CAP theorem” are so confusing!

Consistency The word “consistency” is extremely overloaded in the realm of distributed systems. In CAP, consistency means (informally) that every read reflects the most recent write. This is also known as single-copy consistency or strict / strong consistency. Data is replicated to multiple nodes in these systems, but any reads to this storage system should […]