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Which Filesystem is Best for CompactFlash?

Posted by ryuzaki0 on from the minimizing-writes dept.

HungWeiLo asks: "We're currently using a Debian-based distribution for an embedded device where we're placing our primary kernel and filesystem on a 1GB CompactFlash card. The kernel will be placed in a read-only partition, while the other partition will be used for logging actions in the system and hosting a flatfile database. The concern here is the need to journalize the data (ext2 corrupts pretty badly since we power it on and off), and the need to minimize thrashing of the CompactFlash (we're using industrial-strength, million-write-cycle+ versions, but that can quickly get us into trouble if the filesystem constantly writes to the flash). Does anyone have any experience using filesystems in this situation? Which one should I look into for this type of application? Ext2? Ext3? Reiser? JFFS2? Help!"

3 of 100 comments (clear)

  1. A little large for JFFS2, but that is being fixed by hpa · · Score: 3, Interesting

    Last I talked to David Woodhouse (author of JFFS2), he told me JFFS2 didn't really handle filesystems in the gigabyte range very well, but that that was being remedied in order to support OLPC.

    So if you can wait a bit, then JFFS2 is probably the right answer.

  2. Re:Odd, ext2 works well for me by notarus · · Score: 4, Interesting

    Actually, rereading your original comment, I'm not sure my experiences actually are anything like yours.

    While we update a couple files a few times a month, we're not writing a database to the cf over and over.

    Still, we like the CF based solution-- if we have a hard ware failure, it's quick to swap out, and if the CF fails, we have archives of the file systems made automatically weekly so it's just a matter of untarring to a disk, re lilo'ing, and install.

  3. Re:Doesn't CF already do this for you? by oz_paulb · · Score: 3, Interesting

    I believe all CF flash cards do wear-levelling, so you can just drop a FAT (or whatever) filesystem on top of it without worrying about over-using certain sectors (like the FAT/root dir on a FAT filesystem).

    It sounds like the OP requires journalling - so I'd suggest just choosing any journalling FS that you're comfortable with (and don't worry about whether/not it re-writes sectors a lot, as the CF card will take care of that for you).