Expanding RAID5 guidance

Jeff Boyce jboyce at meridianenv.com
Tue Feb 3 16:58:06 CST 2009


----- Original Message ----- 
From: <christian.peper at kpn.com>
To: <jboyce at meridianenv.com>
Cc: <linux-poweredge at dell.com>
Sent: Tuesday, February 03, 2009 2:39 AM
Subject: RE: Expanding RAID5 guidance


> -----Original Message-----
> Thanks for the advice on the partitions.  It looks like if I
> really knew
> what I was doing I could expand the sda10 (ecosystem)
> partition to take up
> the new space, but none of the other partitions.  From this
> advice I will
> probably consider just adding a new partition and then
> reorganizing my file
> directory system to use it in an appropriate way.  I don't
> think that would
> be too much of an inconvenience to our users (all 9 of them)
> and might be my
> safest approach for minimizing mistakes.
>
> So I am down to needing a few pieces of information:
>    1.  How do I create a new partition sda11 on my expanded
> raid5?  Is this with fdisk?  With disks mounted or unmounted?
Since you'll need to reboot anyway to insert disks and expand the radi5
array, it's best to use a liveCD. Perhaps Fedora or CentOS is best,
since it's very similar to RHEL. This also ensures all disks are
unmounted.

Boot from the liveCD. Login as root.
Go to a shell
fdisk /dev/sda (or use a GUI)
create sda11 on the new expanded RAID array

>    2.  How do I expand the file system?  Is this with
> resize2fs?  With disks mounted or unmounted?
AFAIK you can't expand sda10 to include sda11, not without LVM or so.
So you don't need to resize it. Instead you'll create an ecosystem2 and
add that to the samba server. Perhaps you can move some depts or groups
over to the new share to free up space on the old ecosystem partition.
mkdir /mnt/localdisk
mount /dev/sda /mnt/localdisk
cd /mnt/localdisk

Now you can access the local disk's root system and edit the samba
configuration

>    3.  Then I assume that I need to create a new entry in fstab?
Correct, similar to the existing one with its own mount point. You'll
also have to tell samba about the new share and apply proper file access
rights settings, groups, etc. to it.

>    4.  Then do I need to reboot in order to verify that I
> have the correct entry in fstab?
Yes, you'll doing all this from the liveCD

If things fail, you can reboot using the liveCD.
Since you don't delete any partition, just add a new one, nothing should
get lost or damaged. But you may mistype something in fstab or the samba
config.

Chris.


Thanks for the input Chris.  Someone off-list recommended that I look at the 
GParted LiveCD.  I have looked at this now and it looks like it would be 
easier (i.e., lower probability of making a mistake) for me to use the 
GParted LiveCD for all the work after I reconfigure the virtual disk through 
OMSA.  I may even be able to just expand my sda10 instead of having to 
create a new partition at sda11.  If so, then I won't have to change my 
Samba config file, or modify my tape backup configuration, or even modify my 
fstab.  I am beginning to feel more comfortable now with this task.

Jeff




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