msa2012i questions

[Tom Lyczko]

Hello, I am new to SANs, please bear with me.
We've been recommended by a consultant to get an MSA2000-series SAN.
It looks like the most current version is MSA2012i.
We would use it for a VMware environment.
My questions, having never seen or used a SAN:
1. What is the minimum number of disk drives??
2. Can one mix SAS drives of different speeds or should they all be the same speed??
3. Can one have SAS and SATA drives in the same SAN?? (I assume SAS and SATA would have to be different LUNs??) Though we will likely go with SATA due to cost...budget allows for an ESX HA Kit plus a server plus a SAN.
4. Do I need additional NICs in the ESX servers to connect to the SAN?? The ESX servers already have dual NICs, presently bonded for 2 Gbps throughput.
5. How many NIC cables and power cords?? It seems from the docs at least 2-4 NIC cables and dual power supplies.
This is a very small ESX environment, less than 500 GB now, perhaps a TB by next year, <10 servers.
Evaluating 2 ESX servers plus SAN for business continuity more than disaster recovery, offsite replication etc. is not possible due to low bandwidth WAN connections.

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PS: This thread has been moved from "disk, disk arrays" to "SAN" - Forums Moderator

[Tom Lyczko]

One question I forgot:

6. What is the "LTU" in the HP MSA2000 Snapshot 8 Software LTU software accessory??

I understand this software is for taking snapshots and other aspects of a SAN, how good is it??

Thank you, Tom

[Tom Lyczko]

Can a moderator please re-categorize this thread into the "SAN" category, so I can perhaps receive some replies??

Thank you, Tom

[Chris Rosan]

Tom,

about 3 years ago we purchased an MSA1510cs (which i'd say has been replaced by the 2012 you're looking at). We had about 10 disks in it and didn't need a lot of storage space.

We were running about 6 servers off it (exchange, file/print + a few other "low usage" servers) - including some of them booting from the SAN. These were all physical servers (no virtualisation)

After about 6 months we started seeing bottlenecks on the servers & slow response. We eventually put it down to the fact that all the I/O goes through 1 Smart Array 6402 controller. I have a few ML370 G3's that have the same controller, and on 2 of these box's (they are higher I/O) we were seeing bottlenecks with just 1 server on this card. With the MSA1510cs there were 7+ servers using the one SA card, including for swap.

I had a quick look at the specs of the MSA2012i and couldn't see if it will have the same issue.

I'd suggest if you're going to be running virtual servers you look at the entry level EVA (the EVA4400 now). The controllers in these don't have the same bottlenecks as the MSA family (at least as the MSA1510cs). We have since installed an EVA8100 (top of the range 2 years ago) and i can't through enough I/O at it to get a bottleneck).

You should of course check if the spec's of I/O etc for the MSA2012 will do your job, but can you really predict the number of I/O operations for a virtualised server?

I'm running a host on my EVA (boots from EVA and virtual disks are stored on an EVA volume). It has 4 virtual disks (all "low I/O servers i'll admit - such as the internal anti virus server) but as i said i have no bottlenecks.

I suggest looking at the cost differences between the 2 devices.

For multi-site replication with EVA you need "CA (continous access). Don't think you can do this with the MSA family.

If the restrictions on drive speeds etc are the same as "normal" SA controllers, you can mix drive speeds, but the faster disks will only be as efficient as the slower disks (same as if you have U320 & Ultra 3 disks on the same controller)

Not sure on the SAS/Sata in the same device. You CAN do this with an EVA.

As with any device you can, i'd always suggest dual power supplies for redundancy. Remember, if your SAN loses power then ALL the servers that use it will be down (especially if you're putting the virtual disk files on it).

EVA has full redundancy on everything (2 controllers, 2 power supplies in each controller, 2 power supplies in each disk shelf)

EVA is also more expandable. We bought our EVA8100 with 4 disk shelves, and recently added another 4. From memory i can take it up to 14 shelves.

"LTU" means "licence to use"

Any more questions let me know.