Hi Kai, On 7/17/23, Kai Tomerius <kai@xxxxxxxxxxx> wrote: > Hi, > > let's suppose an embedded system with a read-only squashfs root file > system, and a writable ext4 data partition with data=journal. > Furthermore, the data partition shall be protected with dm-integrity. > > Normally, I'd umount the data partition while shutting down the > system. There might be cases though where power is cut. In such a > case, there'll be ext4 recoveries, which is ok. > > How robust would such a setup be? Are there chances that the ext4 > requires a fsck? What might happen if fsck is not run, ever? Is there > a chance that the data partition can't be mounted at all? How often > might that happen? > Please take a look at this document: https://elinux.org/images/0/02/Filesystem_Considerations_for_Embedded_Devices.pdf In general EXT4 is fine, but it has some limitation, more info here: https://opensource.com/article/18/4/ext4-filesystem I think Linux users suffer from the same problem we have with NuttX (a Linux-like RTOS): which FS to use? So for deep embedded systems running NuttX I follow this logic: I need better performance and wear leveling, but I don't need to worry about power loss: I choose SmartFS I need good performance, wear leveling and some power loss protection: SPIFFS I need good performance, wear leveling and good protection for frequent power loss: LittleFS In a NuttShell: There is no FS that 100% meets all user needs, select the FS that meets your core needs and do lots of field testing to confirm it works as expected. BR, Alan
