Reconfigure of raid-50 on PERC 5/E with OMSA 5.1

Wed Jan 30 05:29:00 CST 2008

Okay, I'll take that into consideration.

I'm pondering this however:

Fill the last 6 slots with 750GB disks and create a raid-5 virtual disk on 5 disks with the 6th 750GB disk as a global hot spare.

As I already have 9 500GB disks in a 8-disk raid-50 virtual disk with the 9th disk as a global hot spare.

What I'm wondering is:

* Can the MD1000 (or PERC5/E) handle 2 global hot spares with different sizes?

       - ie. if a 500GB disk fails will it only use the 500GB hot spare or can the 750GB hot spare be chosen (and thus the raid-5 virtual disk on the 750GB disks would be without a hot spare untill the faulty disk was replaced)?

* If a failure occurs and a hot spare is used, what happens when the faulty disk is replaced? Does the new disk become the new hot spare or is the hot spare disk returned to its "hot spare"-state after rebuild of the array has taken place?

On another note:

What's the status of support for 1TB drives in the MD1000? The current MD1000 support matrix only mentions 750GB SATA as the largest capacity drives, but 1TB drives are readily available..

Regards,

Jens Dueholm Christensen

Rambøll Survey IT

________________________________

From: Patrick_Boyd at Dell.com [mailto:Patrick_Boyd at Dell.com] 
Sent: 28. januar 2008 18:07
To: Jens Dueholm Christensen; linux-poweredge at lists.us.dell.com
Subject: RE: Reconfigure of raid-50 on PERC 5/E with OMSA 5.1

There aren't any controllers of which I am aware that allow reconfiguration of RAID 10 or 50. As for the performance difference I really don't have any data as to which configuration would result in the best performance. My best guess would be that a single RAID 50 would perform better than two concatenated together with LVM, but would probably be very similar to two RAID 50's striped together using Linux software RAID.

From: linux-poweredge-bounces at dell.com [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Jens Dueholm Christensen
Sent: Monday, January 28, 2008 9:58 AM
To: linux-poweredge-Lists
Subject: RE: Reconfigure of raid-50 on PERC 5/E with OMSA 5.1

I forgot to ask:

Are there any newer controllers than PERC5/E that can do reconfiguration of multilevel raid sets, or am I just stuck with the current raid 50 size for now?

Regards,

Jens Dueholm Christensen

Rambøll Survey IT

________________________________

From: Jens Dueholm Christensen 
Sent: 28. januar 2008 16:50
To: linux-poweredge at lists.us.dell.com
Subject: RE: Reconfigure of raid-50 on PERC 5/E with OMSA 5.1

Hi Patrick

Not the answer I had hoped for, but thanks for clearing that up.

Oh well.. I suppose I could always add 6 disks more to the MD1000, build another raid 50 virtual disk on those 6 disks, and then expand the lvm volumes onto that new virtual disk.

Alternativly I'd have to clear all data on the existing virtual disk (~2,7TB), create a new raid 50 set over 14 of the 15 disks and copy the data back, but would that give me any performance as to having 2 raid 50 sets?

On the paper a single 14 disk raid 50 set would probably be "cleaner" than one 8 disk raid 50 + another 6 disk raid 50 set, but would there be any reason (I really can't think of a compelling one) to move all the data just to accomplish that?

Regards,

Jens Dueholm Christensen

Rambøll Survey IT

________________________________

From: Patrick_Boyd at Dell.com [mailto:Patrick_Boyd at Dell.com] 
Sent: 28. januar 2008 16:20
To: Jens Dueholm Christensen; linux-poweredge at lists.us.dell.com
Subject: RE: Reconfigure of raid-50 on PERC 5/E with OMSA 5.1

The PERC 5's do not support reconfiguration of multi-level RAIDs (i.e. RAID 10 and 50).

From: linux-poweredge-bounces at dell.com [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Jens Dueholm Christensen
Sent: Monday, January 28, 2008 9:04 AM
To: linux-poweredge-Lists
Subject: Reconfigure of raid-50 on PERC 5/E with OMSA 5.1

Hi

I'm running out of space on my MD1000 (connected to a PE2950 with a PERC5/e controller) which is populated with 9 500GB SATA disks configured as 1 RAID-50 virtual disk with a global hot spare.

I've read in OMSA 5.1 (havn't upgraded to 5.3 on that system yet) documentation (http://support.dell.com/support/edocs/software/svradmin/5.1/en/omss_ug/html/vdmgmt.html#1295931) that it should be possible to do a reconfigure of the virtual disk, and thus add more physical disks to the virtual disk, but I cannot find 

"Select Reconfigure from the Available Tasks drop-down menu." as step 4 under "To locate this task in Storage Management:" mentions.

What can I do, and how can I expand the raid set?

The documentation mentions (http://support.dell.com/support/edocs/software/svradmin/5.1/en/omss_ug/html/vdmgmt.html#1233595) this:

---

Reconfiguring virtual disks. The Reconfigure task is not available when you have more than one virtual disk using the same set of physical disks. You can, however, reconfigure a virtual disk that is the only virtual disk residing on a set of physical disks. See "Virtual Disk Task: Reconfigure (Step 1 of 3)" for more information.

---

But as far as I can figure out I do not have more than 1 virtual disk, but the "Reconfigure" task is still missing.

I have 2 RAID-1 virtual disks in the same system where I can easily select the "Reconfigure" task in the drop-down menu, so the problem seems to be limited to the disks in the MD1000..

Regards,

Jens Dueholm Christensen 
Rambøll Survey IT

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