William, Yes that works and it's pretty cool. E.g. '/mnt/sdc1' is the disk I added and '/mnt/sagerw' is the union of the read-only compressed /sage file system and my writeable disk, making the whole thing writeable:
# mkdir /mnt/sagerw # mount -t aufs -o br:/mnt/sdc1=rw:/sage=ro unionfs /mnt/sagerw # df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 2063504 2063504 0 100% /initrd/mnt/dev_save /dev/loop1 1887396 62772 1824624 4% /initrd/pup_rw tmpfs 104732 103732 1000 100% /initrd/mnt/tmpfs /dev/loop0 103680 103680 0 100% /initrd/pup_ro2 unionfs 1887396 62772 1824624 4% / tmpfs 128624 296 128328 1% /tmp /dev/sdb1 404470 393319 0 100% /mnt/sage /dev/loop2 389504 389504 0 100% /sage /dev/sdc1 10317828 3279468 6514256 34% /mnt/sdc1 unionfs 10317828 3279468 6514256 34% /mnt/sage-rw # cd /mnt/sage-rw #!/usr/bin/env bash # vi ./sage # Set SAGE_ROOT to the location of the sage install. SAGE_ROOT="/mnt/sage-rw" ... # ./sage ---------------------------------------------------------------------- | Sage Version 4.1.2, Release Date: 2009-10-14 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- The Sage install tree may have moved. Regenerating Python.pyo and .pyc files that hardcode the install PATH (please wait at most a few minutes)... sage: 1+1 2 sage: exit Exiting SAGE (CPU time 0m0.23s, Wall time 0m4.71s). On Tue, Oct 20, 2009 at 12:37 AM, William Stein <[email protected]> wrote: > > By the way, in theory a better way to make /sage "changeable" without using > *any* extra diskspace is to create a new vdi disk, format it, then use > something called "unionfs" to combine the /sage mount with that new > formatted partition. This will make it so /sage still only takes > 380MB, but the changes get stored uncompressed and take precedence > over the read-only content of /sage. I haven't actually done this > yet -- just read about it. But it is one of the key basic ideas on > which the whole design of live cd's, puppy linux, etc., is based > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
