[sclug] Partitioning schemes

[Alex Butcher]

On Mon, 1 Mar 2004, Will Dickson wrote:

> Alex Butcher wrote:
> 
> > Here's my filesystem layout:
> > 
> > Filesystem           1K-blocks      Used Available Use% Mounted on
> > /dev/Volume01/root     4031680   1453764   2373116  38% /
> > /dev/md0                 99470     55082     39252  59% /boot
> > /dev/md1                 99470      4127     90207   5% /boot-spare
> > /dev/Volume01/home     3048336   2545360    348148  88% /home
> > /dev/Volume00/opt      1032088    881024     98636  90% /opt
> > none                    257332         0    257332   0% /dev/shm
> > /dev/Volume01/scratch
> >                       17091652  15171028   1226272  93% /scratch
> > /dev/Volume00/tmp      1032088     35452    944208   4% /tmp
> > /dev/Volume00/usr      6128320   5504264    375020  94% /usr
> > /dev/Volume01/usrlocal
> >                        6379400   6107008     13200 100% /usr/local
> > /dev/Volume00/usrsrc   4128448   3608940    435624  90% /usr/src
> > /dev/Volume00/var      1032088     93892    885768  10% /var
> > /dev/Volume01/varlib    396672    174695    201497  47% /var/lib
> > /dev/Volume01/varspool
> >                        1007896    807524    149172  85% /var/spool
> > /dev/hde1              4087964   2174940   1913024  54% /dosc
> > /dev/hdg1              4087964   2121476   1966488  52% /dosd
> > /dev/hde7              8175980   6180892   1995088  76% /dose
> > /dev/hdg7              8175980   7618972    557008  94% /dosf
> > 
> > This is a system running RH8, plus booting to W98 for games and hardware
> > setup occasionally. Note that I'm using both RAID0 and RAID1 over the two
> > discs, /dev/hde and /dev/hdg. I've rather craftily got two 40G partitions
> > RAID1'd (mirrored) and two 15G partitions RAID0'd (striped). I run LVM on
> > top of them (giving /dev/Volume01 and /dev/Volume00, respectively) so that I
> > can dynamically re-allocate space between partitions on those volumes as
> > demand shifts. Important stuff (/home, /var/spool, ...) is on filesystems
> > contained within the RAID1 volume group, and less important stuff (/usr,
> > /tmp, ...) is on the RAID0 volume group. If a disc dies, I've got a system
> > rebuild to do, but at least my data should be safe. If I had more disc
> > space, I'd go solely with RAID1.
> 
> Whoa! That all looks a bit hairy for me :-) What 
> filesystem(s) do you use?

ext2/ext3. IIRC, you need to unmount and turn off journalling on ext3
partitions before you can use e2fsadm to resize them. After resizing, you
need to re-create the journal before remounting. IIRC, ext2 can be resized
whilst online.

> The reason I ask is that, unless I've completely got the wrong end of the
> stick, you need to be able to resize the filesystem in order for LVM to be
> of use, and resize_reiserfs is still marked as beta. Granted, that group
> seem very conservative about their code quality, so their beta is probably
> equivalent to some other organisations' gold (or service pack 1), but even
> so.

This is true, I suppose. Pick a filesystem whose resize tool works. ;-)

> > Life's too short for statically-sized partitions. If you've only got a
> > single-user machine, don't want to use LVM, and don't mind doing a full
> > backup/restore during OS upgrades, then a large / is probably the next best
> > thing.
> 
> How does LVM save me having to do backup/restores during OS 
> upgrades?

Not so much a feature of LVM, just that keeping all your data (i.e. email in
/var/spool/mail, /home) on seperate partitions from the OS (i.e. / and
/usr). That way, you can keep those partitions unmounted during the upgrade,
and only remount them once you're happy everything's working.

> Ta,
> Will.

HTH,
Alex.
-- 
Alex Butcher      Brainbench MVP for Internet Security: www.brainbench.com
Bristol, UK                      Need reliable and secure network systems?
PGP/GnuPG ID:0x271fd950                         <http://www.assursys.com/>