Expanding RAID5 guidance

[Jeff Boyce]

Greetings -

I am a novice Linux user that manages a file server for a small business and 
am looking for a little general guidance on understanding the right steps 
for expanding the storage capacity on a Dell Server.  Sorry for the long 
post, but I know how irritating it is when people don't describe their 
objective or provide all the details for someone else to understand the 
problem.

Existing Server Setup:
   Dell PE 2600
   PERC 4/Di
   3 - 36GB hard drives in Raid5
   1 - 36GB dedicated hot spare
   No LVM used
   RHEL 3 update 9
   OMSA 5.1
   Used as small office Samba file server

Proposed Objective:
   Add 2 - 36GB drives in remaining spare slots
   Expand Raid5 to include the added space
   Make use of the added space by users of the file server

I know the first rule of thumb with managing raids and file systems is to 
have good backups (multiple backups are better) and I am writing up a 
detailed list of additional files to backup besides my home and data 
directories, so I think I have this covered.  My second task has been to 
make sure that I have a rescue disk or reinstallation disks available in 
case its needed.  If OS installation becomes necessary for some reason I am 
considering upgrading to 5.2 (but that is beside the point).

I have read through the OMSA user guide and feel comfortable going through 
the task to physically install the new drives, and the steps for 
reconfiguring the existing virtual disk.  This point is were my information 
and comfort level begins to fall apart.  The first questions that I would 
like answered is:

1.  How long does the reconfiguration process take (I will do this on a 
weekend when no one is using the system)?
2.  How do I know when the reconfiguration process is done (something the 
user guide doesn't describe)?  As you can see I want to know what to expect 
(good or bad) prior to completing the reconfiguration.

Then from my reading of numerous descriptions of expanding raids through 
google searches (including a decent summary of the steps written by Matt 
Domsch (Expanding Storage on Linux-based Servers, Feb. 2003) it appears that 
I will need to expand the file system to use the new space; but do I also 
need to add/create a new partition for this space, or can I expand an 
existing partition into this space.  What I would like to do is just expand 
one or two existing partitions and distribute this space among them, if that 
is possible (see fstab listed below).  So my next questions would be:

3.  What are the general steps that I need to do after my raid 
reconfiguration is complete to achieve my general objective?
4.  Would it be possible to add the new space to one or two existing 
partitions?  I am thinking sda2 and sda10 (/ecosystem is our samba share 
data directory that would be given 90% of the new space).
5.  Will I need to add/create a new partition (and samba mount point) to 
make use of the new space?  If so I could reorganize our data files to make 
use of two samba mount points.
6.  Any other pitfalls I should be aware of, such as what steps need to be 
done on unmounted drives?

Thanks for any and all comments and suggestions; good howto links are always 
welcome.

FSTAB
-------------------------
LABEL=/                 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext2    defaults        1 2
none                    /dev/pts                devpts  gid=5,mode=620  0 0
none                    /proc                   proc    defaults        0 0
none                    /dev/shm                tmpfs   defaults        0 0
LABEL=/tmp              /tmp                    ext3    defaults        1 2
LABEL=/usr              /usr                    ext3    defaults        1 2
LABEL=/var              /var                    ext3    defaults        1 2
/dev/sda9               swap                    swap    defaults        0 0
/dev/sda2  /home  ext3  defaults 1 2
/dev/cdrom              /mnt/cdrom              udf,iso9660 
noauto,owner,kudzu,ro 0 0
/dev/fd0                /mnt/floppy             auto    noauto,owner,kudzu 0 
0
/dev/st0  /mnt/tape  ext3 noauto,owner,kudzu 0 0
/dev/sda10 /ecosystem ext3 defaults 1 2

RECENT LOGWATCH OUTPUT
------------------ Disk Space --------------------
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda7             2.0G  1.5G  385M  80% /
/dev/sda3             190M   54M  128M  30% /boot
none                  501M     0  501M   0% /dev/shm
/dev/sda8            1012M   33M  928M   4% /tmp
/dev/sda5             9.7G  2.8G  6.4G  31% /usr
/dev/sda6             9.7G  2.9G  6.3G  32% /var
/dev/sda2             2.5G  2.0G  443M  82% /home
/dev/sda10             40G   35G  3.7G  91% /ecosystem


Jeff Boyce
www.meridianenv.com