Ralph, Am 20.05.2017 um 21:36 schrieb Ralph Sennhauser: >>> These days I had an interesting discussion with Christoph about >>> overlayfs and its burden. The main use-case of overlayfs in >>> combination with UBIFS is having a squashfs as lower and UBIFS as >>> upper directory. Such that all changes to the read-only squashfs go >>> into UBIFS. Upon a factory reset all files within the UBIFS will be >>> removed and the merged directory is clean again. Christoph argued >>> that such a functionality could be achieved without overlayfs if >>> the filesystem supported something like pre-seeded files or >>> directories. This would lower memory pressure and complexity. >> >> As you may know, OpenWrt/LEDE have been using this scheme for many >> years now (before it was named overlayfs, this was called mini fanout >> overlay ~10 yrs ago) with squashfs + jffs2 before on P-NOR flashes. >> There are still devices like those that benefit from >> squashfs(ro)+jffs2(rw), so while bringing a similar functionality >> using UBIFS exclusively would be interesting, it would still make >> Linux distribution want to support a more generic scheme which is >> using overlayfs as well. >> > > There is also the size consideration. Unless a seeded ubifs can get > close to squashfs in terms of compression there would still be a > use-case for squashfs with an ubifs overlay. My current root as ubifs > instead of squashfs is 76.8% bigger.
You seem to misunderstand this feature, the goal is not to void all uses of squashfs. I'm pretty sure for the LEDE usecase squashfs is the better choice. Thanks, //richard _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev
