topic Re: MSA 500 G2 - configuring array, etc in Disk Enclosures

MSA 500 G2 - configuring array, etc

ThomasO — Fri, 30 Nov 2007 01:53:01 GMT

Hi All

I am considering to buy a MSA 500 G2.
We are about to run out of disk space on our file server and the MSA in combination with a DL360 G5 looks good.
In addition we might utilize the MSA for storage once we migrate to Exchange 2007 next year.
I am also considering the 4 port I/O module as we might attach a third server as well.

So to my questions
1. From a technology standpoint, is the MSA 500 G2 a good choice? I am not sure when the G2 was introduced, but saw a couple of postings back in early 2005. Should I consider other shared storage solutions? I don't think an EVA is the way to go.
2. From the MSA Q&A page (http://h18006.www1.hp.com/storage/disk_storage/msa_diskarrays/san_arrays/msa500g2/qa.html) question 4 it says "offering up to 2TB of data to be shared with up to 4 ProLiant servers". How come it is only 2TB when the total capacity is 4.2TB (using 300GB disks)?
3. The above question probably leads to how do I configure the array if, let's say, I want to connect 3 servers each with two "disks" presented from the MSA? Do I configure one RAID per connected server or one big RAID (ADG) of all 14 disks and present LUNs to each server?

I was looking for some documentation on this, but didn't find much.

Some help would be greatly appreciated.

Thanks.

/Thomas

Re: MSA 500 G2 - configuring array, etc

Víctor Cespón — Fri, 30 Nov 2007 03:11:56 GMT

OK, let's go step by step. Here you have the quickspecs of both products:
http://h18004.www1.hp.com/products/quickspecs/12476_div/12476_div.html
http://h18000.www1.hp.com/products/quickspecs/11956_div/11956_div.HTML
They are compatible but:
- You need to purchase a SmartArray 6402 for each DL360 G5 to connect the MSA to it
- This implies changing the PCI raiser on the server, as the 6402 is PCI-X and the DL360 G5 has PCI-Express buses.

The MSA 500 G2 is a shared storage device, but it uses SCSI (parallel) connections. There are other MSAs and EVAs but they are connected through fiber channel, so they are more expensive.

The MSA500 G2 has a maximum capacity of 4.2 TB (raw), but the maximum size of a logical drive is 2 TB.

Regarding the question about how to configure the RAIDs, if you make 2 RAIDs, the data on them will be independent from I/O and data protection points of view.

Re: MSA 500 G2 - configuring array, etc

ThomasO — Fri, 30 Nov 2007 05:37:20 GMT

Hi

Thanks a lot for the information.
I found a compatibility matrix where it was stated that DL 320 is the best supported server. I hope that means I don't have to replace back-plane and other parts on that server to get it connected to the MSA?

Regarding the RAID configuration and capacity:
You mentioned that only 2TB will be available. That means that more than 50% will not be available which sounds very strange and doesn't make this a very cost effective solution.
An I missing something here?

Let's say I fill up the MSA with 300GB disks which gives me 4.2TB (raw) capacity. If I want to connect two servers to this MSA (one Exchange and one File Server), each with multiple logical drives. How much space will I have available that I can actually assign to those two servers?

If there is any more detailed documentation on this, it would be great.

Thanks.

/Thomas

Re: MSA 500 G2 - configuring array, etc

Víctor Cespón — Fri, 30 Nov 2007 06:27:23 GMT

I mean 2 TB per logical drive, you can create several RAIDs and several logical drives.
You can create a 14-disk RAID6 and 2 logical drives, or 2 7-disk RAID5 and one logical drive on each. The speed difference is difficult to calculate since RAID6 is slower than RAID 5 but has more disks.
The MSA has a feature called SSP that lets you choose what logical drives each server can see.