Hi, I know BTRFS is a kind of Log-structured File System, which doesn't do overwrite. Here is my question, suppose file A is overwritten by A', instead of writing A' to the original place of A, a new place is selected to store it. However, we know that the address of a file should be recorded in its inode. In such case, the corresponding part in inode of A should update from the original place A to the new place A', is this a kind of overwrite actually? I think no matter what design it is for Log-Structured FS, a mapping table is always needed, such as inode map, DAT, etc. When a update operation happens for this mapping table, is it actually a kind of over-write? If it is, is it a bottleneck for the performance of write for SSD?
What do you think the major work that BTRFS can do to improve the performance for SSD? I know FTL has becomes smarter and smarter, the idea of log-structured file system is always implemented inside the SSD by FTL, in that case, it sounds all the issues have been solved no matter what the FS it is in upper stack. But at least, from the results of benchmarks on the internet show that the performance from different FS are quite different, such as NILFS2 and BTRFS. Any comments? Thanks, Yuehai -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
