# Rupak Majumdar et al. - Why Is Random Testing Effective for Partition Tolerance Bugs? (Highlights)
## Metadata
**Review**:: [readwise.io](https://readwise.io/bookreview/61245024)
**Source**:: #from/readwise #from/reader
**Zettel**:: #zettel/fleeting
**Status**:: #x
**Authors**:: [[Rupak Majumdar]], [[Filip Niksic]]
**Full Title**:: Why Is Random Testing Effective for Partition Tolerance Bugs?
**Category**:: #articles #readwise/articles
**Category Icon**:: 📰
**Document Tags**:: #via/ddia
**URL**:: [readwise.io](https://readwise.io/reader/document_raw_content/463532229)
**Host**:: [[readwise.io]]
**Highlighted**:: [[2026-06-11]]
**Created**:: [[2026-06-13]]
## Highlights
- Most bugs in distributed systems found by Jepsen can be manifested by tests of the following nature (see Section 2 for examples). First, a small sequence of operations łsets upž the system in a special state. Then, a carefully chosen network partition separates the system into two or more blocks which cannot communicate among each other. Then, a further sequence of operations are performed, often in each of the different blocks of the partition. Finally, the partition is healed and a final set of operations are performed. This sequence (perform operations, introduce failures, perform further operations) may need to be repeated a few times at most. ([View Highlight](https://read.readwise.io/read/01ktwhbafgb2jtkmyemg0pqmqz)) ^1024487775
- A k-partition splits processes ai1 , ai2 , . . . , aik if these processes all end up in different blocks of the partition. ([View Highlight](https://read.readwise.io/read/01ktwhmbpy6x22r7rj4wm5tkpd)) ^1024488187
- This is formalized using the notion ofseparating coverage: for fixed k,l > 0 and every pair of collections ofk and l roles, separating coverage requires that the collection ofk roles is separated by a partition from the collection of l roles. ([View Highlight](https://read.readwise.io/read/01ktwhnf93v1nb0x9xdca8q44c)) ^1024488202
(k,l)-Separation: in every (k, l) groups, k and l are separated.
- minority isolation: for each process, this coverage notion requires that the process is in the smaller block of a bipartition. ([View Highlight](https://read.readwise.io/read/01ktwhrrehznh7ewbhx30np1zb)) ^1024488341