Extending a Logical Drive on a MSA1000 in Windows 2003...

[Nolan Northup]

I have three logical drives on a MSA1000. I would like to extend Logical Drive 2. If I extend Logical Drive 2 then run the diskpart utility and the extend command will this work. My only worry is the space is not contiguous as the Microsoft documents explain.

[Uwe Zessin · Accepted solution]

Nolan,
can you give a pointer to this document? It is not clear to me what Microsoft means by non-contiguous.

[Steven Clementi]

Windows will see the new space as contigous since your adding space to a single drive. If, by chance, you have several partitions on that one drive, then you may run into a problem expanding the partition, but only if you have a basic disk. Dynamic disks allow expansion of a partition where the addition space is NOT contigous on the same drive.

Click here for diskpart info (though you probably seen this already..
http://support.microsoft.com/default.aspx?scid=kb;en-us;325590


Steven

[Steven Clementi]

also... though it may not be contiguous on the MSA, windows does not "see" that. It only sees that you have added space to a Logical Drive, making it look contiguous.


Steven

[Uwe Zessin]

Steven,
I think a logical disk is always contiguously stored within a disk array as you can only delete them in reverse order from a disk array.

[Nolan Northup]

Here is the MS article I was referring to.
http://support.microsoft.com/default.aspx?scid=kb;en-us;304736&Product=winsvr2003

[Nolan Northup]

Uwe that is exactly what I am worried about.

[Uwe Zessin]

Ah, OK, but even if it were non-contiguous an the MSA (like on the EVA) it would not be problem if you extend an existing logical disk. This is because (Steven already said it) Windows is presented the same LUN which just got more space at the end.

What Microsoft talks about is when you expand an existing disk array with additional physical disks. This gives you free space within the disk array which you can use to either expand existing logical disks and/or create additional logical disks. The latter one will appear als new LUNs on Windows.

Of course I would still do a full backup before I started, because it is too easy to screw things up - computers are SO unforgiving!!

[Steven Clementi]

That still does not effect how Windows see's the drive. Windows will still see free space on the existing Logical Drive as long as you have expanded the logical drive, not created a new logical drive. That is all Windows cares about.

Logical Drives do not need to be deleted in reverse order either on the MSA1000, at least it was not like that with the last one I worked on. As well, expanded space can never be contiguous since data has already been written to the drives. The MSA controllers handle that though and it is transparent to the host system.

In the case that you want to expand a Cluster resource, I would suggest that definitely do a complete backup, shut down one node of the cluster, stop all activity on the node that is alive and run diskpart. Once complete, bring up the second node and failover the resource to make sure it sees the expanded space.

Steven

[Steven Clementi]

HAHhahahaha, it seems like we are crossing paths and time differences. Also, I just read the MS article you posted Nolan and it suggests the same course of action.

Steven

[Nolan Northup]

Thank you both Uwe and Steven. I can not find a whitepaper from HP that is on point. I do want to mention that I cannot delete logical volume 2 with out deleting 3. I do have the latest firmware loaded and ACU software. Thank you though this helps alot.

[Steven Clementi]

My mistake If I remember correctly, you can not delete a logical drive in the same array.

I was, on my prvious project, deleting LUN 2 before LUN 3, but they were on different arrays. I need an MSA to play with. (preferrably the MSA1500 with 24TB storage in an 18U footprint).

So the truth is, you would have to delete 3 to delete 2 in the same array. You don't need to worry about that though since the controllers handle the expansion and Windows just see's free space on the same drive.

Steven

[Uwe Zessin]

Well, last time I checked (didn't do so on the lates firmware release) I was able to assign unit numbers in any order I wanted.

But if I created logical disks on one disk array with units: 5, 7, 1 then I could only delete them in order: 1, 7, 5. I hope this explains it better.