"Here is a new flash file system developed by Nokia engineers with help from the University of Szeged. The new file-system is called UBIFS, which stands for UBI file system. UBI is the wear-leveling/ bad-block handling/volume management layer which is already in mainline (see drivers/mtd/ubi)," began Artem Bityutskiy. He explained that UBIFS is stable and "very close to being production ready", aiming to offer improved performance and scalability compared to JFFS2 by implementing write-back caching, and storing a file-system index rather than rebuilding it each time the media is mounted. The write-back cache implementation claims to offer around a 100 time improvement in write performance over JFFS2. Artem went on to note:

"UBIFS works on top of UBI, not on top of bare flash devices. It delegates crucial things like garbage-collection and bad eraseblock handling to UBI. One important thing to note is MLC NAND flashes which tend to have very small eraseblock lifetime - just few thousand erase-cycles (some have even about 3000 or less). This makes JFFS2 random wear-leveling algorithm to be not good enough. In opposite, UBI provides good wear-leveling based on saved erase-counters."

Jörn Engel announced LogFS, "a scalable flash filesystem." The project's home page notes that LogFS aims to be the successor of JFFS2, "the two main problems of JFFS2 are memory consumption and mount time. Unlike most filesystems, there is no tree structure of any sorts on the medium, so the complete medium needs to be scanned at mount time and a tree structure kept in-memory while the filesystem is mounted. With bigger devices, both mount time and memory consumption increase linearly. JFFS2 has recently gained summary support, which helps reduce mount time by a constant factor. Linear scalability remains. YAFFS also appears to be better by a constant factor, yet still scales linearly."

In contrast, Jörn compared his new LogFS, "LogFS has an on-medium tree, fairly similar to Ext2 in structure, so mount times are O(1). In absolute terms, the OLPC system has mount times of ~3.3s for JFFS2 and ~60ms for LogFS." Regarding its stability, he noted, "LogFS works and survives my testcases. It has fairly good chances of not eating your data during regular operation. There are still two known bugs that will eat data if the filesystem is uncleanly unmounted. Also still missing is wear leveling." Thomas Gleixner reviewed the code and offered the following summary, suggesting the code has a ways to go before it replaces JFFS2, "the code is far from being useful on real world hardware. The error handling via BUG() is just making it useless. Also please fix the coding style and other issues from the seperate review. Some useful comments would make a functional review way easier."