I just read [0] and have some notes and questions to share. [0] http://elinux.org/images/b/b6/EMMC-SSD_File_System_Tuning_Methodology_v1.0.p... Questions: - the FTL is opaque to the user and the OS. Where can I find a mapping of make/models to FTLs? For SSDs that would be the make/model of the SSD, but for SD I believe the FTL is implemented in the reader, not in the SD card. Where can I find honest (i.e. independent) analysis of FTL metrics? - Max claims bonnie++'s functionality is superseded by fio. Russell, you maintain bonnie++, right? What's your opinion of fio? Notes: - p 9 flashbench helps you guess the erase block size. - pp 10-12 lists fs and scheduler optimization knobs. - p 13 btrfs likes -o ssd if device speaks TRIM. ext4 likes noatime/nojournal, CFQ and discard. CFQ is best for most things, then ROW. - p 23 optimal configuration differs between device make/model. optimzation helps r/w loads more than r/o or w/o loads. - p 26 avoid btrfs/f2fs if OS can be reset by unscheduled power outage or hardware watchdog, unless you have a BBU or similar. ext4 survives many more outages than btrfs/f2fs.