Hey, On Wed, 2011-07-13 at 10:32 +0200, Karel Zak wrote: > Good point. There is demand for a generic API to assemble block > devices (dm-crypt, MD, LVM, loopdev, ...). This functionality has > been requested by desktop guys, dracut, udev and it seems also > attractive for mount and fsck. I'll probably start to work on this > task at the end of this year (I hope with DM guys). > > The idea is to have a simple library (libblkasm ?) that provide API > to assemble a block device according to the configuration in > /etc/fstab and /etc/blkasm.d/. The library should be modular, so > subsystem specific modules (lvm.so, crypt.so, ...) will be maintained > externally by subsystem developers. It seems like a good way how to > keep the functionality up to date and minimize some communication > problems between people :-) > > Note that the original idea is from David Zeuthen > http://people.freedesktop.org/~david/stc-20101011/stc.conf.html, but > David's goal was daemon. FWIW, I've changed my mind about this. Basically, I don't think it's worth supporting fake block devices (except for dm-luks and maybe loop devices). Specifically, I will not support it in the next major version of GNOME Disk Utility (aka Palimpsest) except for showing the "friendly" dm name (e.g. /dev/mapper/blah) instead of /dev/dm-0. Here's a work-in-progress screenshot http://people.freedesktop.org/~david/palimpsest-with-fake-block-devices.png (Compare to: http://people.freedesktop.org/~david/nautilus-lvm2-b.png ) Anyway, I think it would be better if people instead worked on e.g. btrfs and making we properly support multi-disk in btrfs... because btrfs multi-disk is subject to exactly the same problems as you have when activating RAID or LVM devices (except that you can't do arbitrary trees - which is a good thing!). For example, there's a policy decision when to start a device in degraded mode. And, IIRC, the kernel don't even properly convey what underlying devices a btrfs fs is currently using (it didn't last time I checked which is ~12 months ago). David -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
