Hi, > First of all, I am thinking now and I will think that defragmentation should > be > a part of GC activity. Usually, from my point of view, users choose NILFS2 > because of using flash storage (SSD and so on). So, GC is a consequence of > log-structured nature of NILFS2. But it needs to think about flash aging, > anyway. > Because activity of GC or other auxiliary subsystems should take into account > NAND flash wear-leveling. If activity of auxiliary subsystems will be > significant > then NAND flash will fail soon without any clear reasons from an user's > viewpoint.
I have no idea of the actual implementation or the code, so my comment just represents the POV of a fs-user. I've tried Nilfs2 and Btrfs (both cow) on traditional mechanical harddisks to get cheap, efficient snapshoting. However, due to cow, files with high random-write activity (like firefox's internal sqlite database) fragmented so heavily those filesystems were practiacally unuseable on HDDs. Btrfs actually offers both, manual defragmentation as well as an autodefrag mount option - which is useful even for SSDs when the average continous segment size becomes as low as 4kb. While autodefrag would be great for nilfs2, a manual tool at least wouldn't hurt ;) Regards -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
