larch – a do-it-yourself live Arch Linux CD

/etc/fstab and mount points

The file /etc/fstab determines mount points for the various devices and partitions available in the system. This is of course different in every computer, so a live CD has to be pretty flexible here. larch handles this by regenerating this file each time it boots, basing the content on the devices it discovers in the present system.

Disk partitions are not mounted automatically by larch, as one of the main purposes was to act as an installation CD - for partitioning and formatting the partitions must be unmounted. But each detected disk partition and CDROM device should get an entry in '/etc/fstab' and a corresponding mount point in '/mnt'. Thus they can be mounted using 'mount /mnt/DEVICE' (or by using, say, KwikDisk in KDE).

It may however, under certain circumstances, be desirable to have a persistent '/etc/fstab'. This can be achieved by placing "#KEEP" (without the quotation marks) at the beginning of a line in '/etc/fstab'. This could be done when making the original CD by putting the desired '/etc/fstab' file in the overlay, or else - in the case of a rewritable boot medium (e.g. USB-stick) - by editing '/etc/fstab' while running the live system and then performing a session saving reboot. A new '/etc/fstab' (and the associated mount points in '/mnt') can be generated at any time while running larch, by executing 'gen_fstab -l'. This might be useful after repartitioning, for example. When the '-l' option is omitted, no updates are made, but the proposed changes are saved to '/tmp/fstab' and '/tmp/mnt'.

LVM

larch can also handle LVM volumes, including automatically generating entries in '/etc/fstab' and mount points in '/mnt'. This must however be enabled in '/etc/rc.conf' (e.g. by putting the required entries in 'rcconfx' in the profile used to build the larch system). USELVM="yes" must be set and the module 'dm-mod' must be loaded (this is done automatically when USELVM="yes" is set). The supplied 'mini2' and 'xmini' example profiles contains this feature, and can thus be taken as an example.