Part of the problem you will encounter is that Linux needs certain directories available at boot time before /etc/fstab mounts any other disks. These include, but are not necessarily limited to:
/boot /sbin /bin /etc /var /tmp In other words, all of these have to be on the boot volume at boot time. /var and /tmp have to be r/w and the others can be r/o, but since they're all on the same disk it's best to just make everyting r/w. At boot time, a small amount of memory is needed until the swap device is mounted. After things have booted to the point where /etc/fstab is read and the new mount points are mounted, then you can add things into it like /usr (most of the dasd space used in Linux/390 is here.) /home /opt We give each Linux instance its own boot disk, dasdb (500 cylinders of 3390-3), and use swap in V-disk (dasda). then we mount /usr shared read-only as dasdc (3338 cylinders) and each Linux gets its own /home read/write as dasdd (or more with LVM), sized to the particular user's needs. We're currently experimenting with different shared read-only /opt disks depending on if the user needs db2, websphere, oracle (beta-test version) and the like. Don't get too fancy with multiple disks or it'll end up being a management nightmare. Just making /usr shared r/o is problem enough. Some users want to update /usr by adding their own .rpm's, but the rpm databases are in nonshared /var/lib/rpm. If you want to know what's using the disk space in your system, cd to / and type the command du --max-depth=1 -h "You do not need a parachute to skydive. You only need a parachute to skydive twice." -Motto of the Darwin Society Gordon W. Wolfe, Ph.D. (425) 865-5940 VM Technical Services, The Boeing Company > ---------- > From: Arty Ecock > Reply To: Linux on 390 Port > Sent: Tuesday, March 12, 2002 12:15 PM > To: [EMAIL PROTECTED] > Subject: R/O Linux guest? > > Hi, > > I need to set up a Linux/390 guest with read-only file systems (and > minidisks). Has anyone done anything like this? I'd want to put the > portions of the file systems that MUST be read-write on a V-disk. > > My filesystems are all on separate minidisks: > > / > /home > /usr > /opt > /tmp > /var > swap > > I think I can make /usr, and /home read-only rather easily. The same > with /opt. For the others, I'd have to disect them to locate the files > that must be read-write and set up symlinks for them. Am I on the right > track? > > Cheers, > Arty > >
