TIL One of the weirder UX quirks of NFS between Host and Guest machines (same metal) A file can look completely frozen the first time you open it even when nothing is wrong First open: 7-12 minutes Second open: fast Open another uncached archive? Frozen again Is it downloading? Not like a browser download No progress bar No loading spinner The app thinks it's a local read on a mounted folder The kernel still has to pull those file pages over NFS into RAM first The process just waits Looks hung Why another archive freezes too The cache is for the data you've already read Not for the NFS server in general Archive A, first open Those pages aren't in RAM Kernel fetches them from the NAS Slow Archive A, second open Same pages already in RAM Fast Archive B, first open Different file Different pages None cached Kernel fetches again Hung again Another funny one A CBZ is a ZIP The reader has to walk a chunk of it before it can show you anything Over slow NFS that looks frozen, not loading The system learned Archive A Not the filesystem Each new uncached archive pays the remote I/O tax again Same file. Same server. Nothing corrupt. Your bytes are coming, eventually Distributed filesystems are fun