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MSA20 SATA Logical Drive - 2TB+ ??

 
Graeme Watson
Occasional Advisor

MSA20 SATA Logical Drive - 2TB+ ??

I have a fully populated HP MSA20 disk shelf with 3TB of SATA drives (12*250GB)

The maximum logical drive size I can create is 2097151MB or approx 2TB.

Is there anyway around this? I require the full 3TB minus 250GB for Raid 5.

I have upgraded the firmware for both MSA20 and the server (DL360). I have also upgraded to Windows 2003 SP1 since it now supports logical drives larger than 2TB, but still nothing. Any ideas?

Thanks in advance

Graeme
11 REPLIES 11
Steven Clementi
Honored Contributor

Re: MSA20 SATA Logical Drive - 2TB+ ??

Graeme:

2TB is a hard limit on the MSA controller and has nothing to do with the OS.

The only way around it would be to create 2 Logical Drives and span them via the OS.



Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Graeme Watson
Occasional Advisor

Re: MSA20 SATA Logical Drive - 2TB+ ??

Steven,

It's not so much the partition size in Windows that bothers me it's the fact that because I have to create two logical drives I end up loosing 500GB to raid rather than just one disk of 250GB, could have done with the extra space.

Oh well, if there's nothing I can do then....

Thanks

Graeme
Steven Clementi
Honored Contributor

Re: MSA20 SATA Logical Drive - 2TB+ ??

If you are creating 2 logical drives int he same Array, you should get the same amount of drive space as if you created 1 full sized logical drive.


If you have, lets say, 300GB available for RAID5 and you create 1 150GB RAID5 Logical Drive, you still have 150GB available for RAID5, you do not lose more space. The initial lose is based on the Array as a whole, not each individual drive.

I remember proving this to myself awhile back and believe the resultd have not changed. Checking again though...


Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Steven Clementi
Honored Contributor

Re: MSA20 SATA Logical Drive - 2TB+ ??

See attached image....


In the top half, I showed available RAID5 space.

In the bottom half, I showed available space after creating a RAID5 LUN @50% of original space...

80831+80835 = 161666, the same original RAID5 Available space.


Cheers,

Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Graeme Watson
Occasional Advisor

Re: MSA20 SATA Logical Drive - 2TB+ ??

Steven,
That kind of makes sense now, I think it's down to my calculations. I was expecting to see a figure of 3145728MB of space not 2861318MB which is actually available, however that's not the case.

When I select the controller I can see 12 slots full with 250TB or disks.

I then click on Create Array, select all disks. I then select the unused space (2861318MB) and click on creat logical drive. The maximum logical drive I can select is 2097151MB RAID 5. I can then create another drive RAID5 of 573515MB.

See attached file, not that it's much help.

Graeme Watson
Occasional Advisor

Re: MSA20 SATA Logical Drive - 2TB+ ??

Although it does look strange when you examine the physical view. See attached pic.
Steven Clementi
Honored Contributor

Re: MSA20 SATA Logical Drive - 2TB+ ??

What's weird about the physical view? (Aside from how HP engineered the way the buses work.)


Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Graeme Watson
Occasional Advisor

Re: MSA20 SATA Logical Drive - 2TB+ ??

Steven,

Just seems weird why there are 8 disks in one port and 4 in the other. I would have thought to make 2TB you would have need 9, 8*250GB and 1 for Raid?

Am I making any sense, or just bein stupid? :)

G
Steven Clementi
Honored Contributor

Re: MSA20 SATA Logical Drive - 2TB+ ??

Your just looking at it improperly.


Your Array view is showing which disks in your shelf are being used for the array, not per Logical Drive.

The Bus on the MSA20 is split and has 2 ports, similar to a dual channel MSA30. The controller has the ability to use drives from either port and in this case, is using all 12 drives.

If you had multiple Arrays, when you click on a particular array in ACU, the physical drives used by that array should blink. In your case, since all the drives are in 1 array, they all should be blinking all the time while in ACU.



Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Graeme Watson
Occasional Advisor

Re: MSA20 SATA Logical Drive - 2TB+ ??

ah... thanks for clarifying that.

What do you think about;

"I was expecting to see a figure of 3145728MB (12*250GB) of space not 2861318MB which is what's actually available" I then end up with 2605318MB of actual usable space after raid5"
Steven Clementi
Honored Contributor

Re: MSA20 SATA Logical Drive - 2TB+ ??

"I was expecting to see a figure of 3145728MB (12*250GB) of space not 2861318MB which is what's actually available" I then end up with 2605318MB of actual usable space after raid5"


The difference in Unused and Available for RAID5 seems right. 2.86 - .250 = @2.61TB

The difference in calculated size and actual unused space I thought would be attributable to the difference in "sold capacity" vs. "actual capacity"

I calculated the actual disk capacity to be @ 244GB (and I could be off a little). 244*12 = 2.93TB minus some overhead for Array Configuration/meta info = 2.86TB Usable. (yes, a discrepency of 70GB... I can't explain it, but I also think my calculation is off a bit as well.)


Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)