Johannes Franz, writingJohannes Franz is a software engineer. Photographs, engineering work and writing.https://johannesfranz.com/What fsync actually promiseshttps://johannesfranz.com/writing/what-fsync-actually-promises/https://johannesfranz.com/writing/what-fsync-actually-promises/When write() returns, your bytes are in the page cache, not on the disk. A walk through each layer between the syscall and the platter.Fri, 02 Oct 2026 00:00:00 GMTstoragelinuxShipping a site under 50 KBhttps://johannesfranz.com/writing/shipping-a-site-under-50-kb/https://johannesfranz.com/writing/shipping-a-site-under-50-kb/How this site stays small, and why every page prints its own weight in the corner.Tue, 18 Aug 2026 00:00:00 GMTwebperformanceNotes on Raft, from scratchhttps://johannesfranz.com/writing/notes-on-raft-from-scratch/https://johannesfranz.com/writing/notes-on-raft-from-scratch/Working notes from implementing Raft without looking at an existing implementation.Sun, 30 Nov 2025 00:00:00 GMTdistributed systems