Bootloader question (ext2/3 filesystem format evolution)

John Gilmore gnu at toad.com
Wed Jun 3 22:23:48 EDT 2009


> I'm thinking about ext4, but I must confess that my experience with ext2 
> has been pretty frustrating. The ext2/3 on-disk format has sprouted many 
> new features over time.  Supporting people who plug in disks that are 
> formatted with the latest fancy feature, then complain that an old 
> firmware release fails to work with it, is difficult.

I just experienced this yesterday, plugging a new PATA 750GB disk
drive into an Ubuntu 9.04 system, doing parted and mke2fs -j on it,
then moving it to a Red Hat 7.3 system.  Not only did RH7.3 parted
complain about the alignment of the partition table, but the kernel
would not mount the ext3 filesystem AT ALL, because Ubuntu had
silently created it with 256-byte inodes rather than 128-byte ones,
and the old kernel didn't support 256-byte inodes.

The disk was empty, so I took the lesson and reformatted it *from the
old system* rather than from the new system.  Now it works with both.

	John



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