On Saturday 15 May 2010, Matt Brown wrote: > Hi, Hi Matt, > > 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. > > For example, I have a system that has a btrfs raid1 as root. However, I > had to patch the boot loader (dracut) so during boot it would scan just > before mounting the root filesystem. > > I filed a bug with dracut, but the more I think of it, the more it seems > that either mount.btrfs should be taking care of this, or another part > of btrfs. If it would be mount.btrfs to perform the scan, that means a scan for every mounting. I think that is better to separate the two function. The scan has to be performed a device discovery time, and not a the mounting time. > > Any thoughts or plans on the matter? > > Thanks, > Matt BR Goffredo > -- > 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 > -- gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreijackATinwind.it> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- 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
