On Sat, May 15, 2010 at 06:47:22PM +0200, Sebastian 'gonX' Jensen wrote: > >> Would it be possible and feasible to support mounting btrfs > >> raid/multi-device filesystems without having to run 'btrfsctl -a'? > >> > >> Currently, as you may know, if a one wants to attach a btrfs raid > >> filesystem to a system (usb, hotswap, reboot, etc), the user or program > >> has to run: > >> > >> btrfsctl -a (or similar) > >> mount /dev/sdb1 /mount/point > >> > >> While this works, it will require patching of various subsystems > >> involved with managing disks, such as udev, mkinitrd, dracut, hal, and > >> others. Each one will have to know to scan, then mount. > > > > In a my previous post ([RFC] btrfs, udev and btrfs - 16/April 2010), I > > suggested a solution for this kind of problem. I a Debian/Ubuntu system it is > > not necessary to patch anything, it is only required to put some files in the > > initramfs-tool configure directories. > > > > IIRC, also the md (RAID) subsystem require a scan from the user space to find > > and activate the volumes. I think also dm (LVM) subsystem requires the same. > > > > md does not require a scan from userspace with at least both RAID-0 > and RAID-1. There's a setting in the kernel config you can set, which > will automatically detect all RAID drives with the FD partition flag > set. DM may however be true. MD will only detect RAID on MS-DOS partitions (seldom used when RAIDing whole devices, not possible to use with devices >2 TiB) and metadata 0.90, which is not default. Userspace probing is general way kernel subsystem are going, it is more flexible. And dracut already has btrfs module. -- Tomasz Torcz ,,If you try to upissue this patchset I shall be seeking xmpp: zdzichubg@xxxxxxxxx an IP-routable hand grenade.'' -- Andrew Morton (LKML) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
