2xMSA70 2xDL360G6 Dual Domain Setup

[wobbe]

I got the following new hardware.

2x MSA70 with dual domain controllers
2x DL360G6
2x P800 Controller
and some cables.

I want a setup where each server gets can create raid 1+0 sets, using the P800 controller, that are mirrored across both MSA boxes.

How do I setup the cabling?

[TTr]

The dual domain document is here.

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01451157/c01451157.pdf?jumpid=reg_R1002_USEN

It does not look like the configuration you are trying to achieve is supported but I would try the wiring diagram on page 7.
It is for one server, one controller, one i/o module and 3 disk enclosures. I would put the second server in the second i/o module and cut the picture down to two enclosures.
Each P800 would see all disks. You would decide which disks would be used by each controller.
Note that only one port to each disk is used in the picture. The second port would come from the second i/o module and the second P800/server. If one P800 used a disk from one port, there could be interference coming from the other controller through the other port in this case. If that intereference is no more than a sense signal this might work, otherwise each controller would scre up the other controller's disks.

I would be interested to see if it works.

[wobbe]

Mmm, creating a "circle" feels a bit unnatural but I'll give it a try.

At the moment i have the following setup.

P800(1) Server 1
Port 1 connects to I/O 1 on MSA1
Port 2 connects to I/O 1 on MSA2

P800(2) Server 1
Port 1 connects to I/O 2 on MSA1
Port 2 connects to I/O 2 on MSA2

I've created some volumes on server 1 and they seem to work. Server two sees those volumes as failed.

I've added some extra disks. Server one sees them and can create a raid volume. Server two doesn't see the extra disks at all.

(My reseller told me I could create this configuration)

[TTr]

This is similar to what I suggested except that you are not cascading between the two MSA60. Each port of the P800s is isolated to one MSA70 only.

[wobbe]

Yeah, but at the moment I'm only using the left connectors on the I/O modules.
When creating a loop need to connect left to right (or the other way around)
It looks to me like a completely different setup. I'll head over to the server room now and give it a try.

[TTr]

I am not saying my wiring sugestion is better than the one you are using now. In both cases the SAS drives have one port going to one controller/server and the other port going to the other controller/server. So if you use one drive in one controller raid you must leave it unused in the other controller. So if the "other" controller sends any kind of signal to that drive, it might interfere with the raid configuration of that drive in the first controller.

[wobbe]

I tried a few different cabling options but with the same results. I get the impression that this just won't work. Perhaps I could try that clusting option (page 6) but that seems to be for one MSA.
If I only could insolate raid volumes between controllers.

[Pieter 't Hart]

Hi, wobbe,

I don't think you can compare the MSA70 to a SAN where you can use zoning to present volumes to different hosts.
Your setup is basically two hosts on a shared SCSI-bus.

Both hosts can see all disks, and don't know that another host is accessing the disk.
You'll end up with disks controlled by host-1 and in error on host-2. But every reboot can change this around.

Here's where clustering software comes in.
This does the communication between the hosts to manage locks on disks etc.

The dual doamin-option gives you redundant paths from host to storage, the clustering gives you redundent hosts.

You'll need a more intelligent storage system, not with just dual I/O modules, but with a storage controller in the storage system instead of the hosts,
or use clustering software.

[wobbe]

I also get the impression that this never will work they way I want it to.
I'm getting pissed a my suppier. There storage guy came up with this config as a replacement for our dual contoller MSA30's.