Expanding LUNs with Navisphere

I need to expand a couple of LUNs and am seeking advice regarding how
to proceed.

We are using a Dell/EMC Clarion 300. We have two RAID groups (1 and 2)
that had multiple LUNs on each RAID group with the LUNs assigned to
different servers (I know, bad idea). Only one server uses the two RAID
groups now and I'd like to allocate all space in each RAID group a
single LUN in each RAID group (i.e., Expand LUN 12 to use all disk
space in RAID Group 1 and expand LUN 21 to use all disk space in RAID
Group 2).

RAID Group 1:
Server F is using 60 GB (LUN 12) on RAID Group 1 (configured as RAID
1).
73 GB on RAID Group 1 is free and unallocated (no LUN created).
I want to allocate this unused 73 GB on RAID Group 1 to Server F (i.e.,
expand LUN 12 to use the additional 73 GB).

RAID Group 2:
Server F is using 250 GB (LUN 21) on RAID Group 2 (configured as RAID
5).
Server B was using 250 GB (LUN 22) on RAID Group 2.
300 GB on RAID Group 2 is free and unallocated.

I want to allocate the 250 GB (LUN 22 assigned to Server B) to Server F
and allocate the 300 GB unallocated space to Server F (i.e., expand LUN
21 to use all the space on RAID Group 2).

None of the LUNs are part of a snapshot, clone, mirror or SAN Copy
session.

Regarding RAID Group 1:
Do I need to create a LUN from the unallocated 73 GB on RAID Group 1,
then expand LUN 12 using the Expand Storage Wizard?
If so, when I expand the LUN do you recommend I choose Stripe or
Concatenate Expansion?

Regarding RAID Group 2:
Do I need to destroy LUN 22, then create a LUN using the unallocated
space, then expand LUN 21 using the Expand Storage Wizard?
If so, when I expand the LUN do you recommend I choose Stripe or
Concatenate Expansion?

Many thanks in advance to the group for any guidance.

Jeff

Here is what I understood from your statements.

1. on RAID group 1, you want to combine the LUN 12 and free space and
give it to server F
2. on RAID group 2, you want to combine the LUN 22 and free space and
give it to server F, disconnecting LUN 22 from server B.

So at the end, server F will be happy to get all the large LUNs.

okay..
Do I need to create a LUN from the unallocated 73 GB on RAID Group 1,
then expand LUN 12 using the Expand Storage Wizard?
Yes, you need to create new LUN and then add it to existing LUN using
MetaLUN feature of Navisphere.

If so, when I expand the LUN do you recommend I choose Stripe or
Concatenate Expansion?
You will have to go for Concatenation in your case if you wish to
utilise all the space you have.
Striping can be used on CLARiiON when LUNs being expanded are
1. on same type of RAID groups (e.g. LUN from RAID 1 and RAID 5 cannot
be combined).
2. are of same size. in your case, LUN 12 is 60GB in size. you cannot
create a LUN of 73GB on free space and stripe it together.
3. (This will apply to Release prior to 19) When the LUN being expanded
is more than 1 TB in size)

Do I need to destroy LUN 22, then create a LUN using the unallocated
space, then expand LUN 21 using the Expand Storage Wizard?
No, just create a new LUN and expand LUN 22 using it.

Concatenation would let you access new expanded space within minutes.
Striping would take long time since data is redistributed among all
drives in the metalun.

If
- LUNs do not store any critical data at the moment
- there is no much IO going on the array
then you can just drop existing LUNs and recreate a big LUN of whatever
capacity you need on each RAID group. that would be much faster. It
would give you a performance benefit also.

hope that helps.

Kiran Ghag
http://www.kiranghag.com
EMC Proven- CLARiiON Solutions and Implementation Specailist
SNIA Certified Professional - 2006