Hi! The no-unsafe-io workaround in dpkg was needed for 2005-era ext2fs issues, where a power-cut in the middle of filesystem metadata operation (which dpkg does a lot) might result in in unconsistent filesystem state. This workaround slowed down dpkg operations quite significantly (and has been criticised due to that a lot, the difference is really significant).
The workaround is to issue fsync() after almost every filesystem operation, instead of after each transaction as dpkg did before. Once again: dpkg has always been doing "safe io", the workaround was needed for ext2fs only, - it was the filesystem which was broken, not dpkg. Today, doing an fsync() really hurts, - with SSDs/flash it reduces the lifetime of the storage, for many modern filesystems it is a costly operation which bloats the metadata tree significantly, resulting in all further operations becomes inefficient. How about turning this option - force-unsafe-io - to on by default in 2025? That would be a great present for 2025 New Year! :) Thanks, /mjt
