HP P2000 G3 Directed Connected

[Johan Guldmyr]

Well, is it normal to get more than 400MB/s (or whatever 4Gbps amounts to) from one disk shelf?

Probably with the SFF shelf (so max is 24 disks on one shelf).

But if you're doing this kind of on the cheap I presume you'll use 7200 RPM SAS/SATA disks?

[Alysson]

I see. I plan to use a mix of SAS (15k) and SATA (7.2k) disks.

[Alysson]

We just bought the P2000 G3 and I got another question:

In a implementation with one host directed connected to controller A and another host directed connected to controller B, could a volume owned by controller A be accessed by a host that's connected to controller B?

Thanks in advance.

[Alysson]

Just to clarify , in the question above I meant a case in normal operation, without controller failure.

[Torsten.]

Let's assume you have 2 servers, the array has 4 FC ports.

You should connect
server A to ports A1, B1:
server B to ports A2, B2

for redundancy.

You can now create 2 vdisks with volumes, one for server A, another for B, each owned by one controller, if you like.

[Alysson]

Actually, I know that's not the best solution and later we'll get a switch to improve the implementation, but I plan to direct connect a third host to the storage and in this case I won't be able to connect servers A and B to both controllers.

I am almost convinced that during a normal operation a host directed connected to a controller won't be able to access the volume owned by the other controller, but I need to be 100% sure on this.


Thanks.

[Torsten.]

You can always change the preferred owner of a vdisk.
You should access the volumes via the preferred owner for performance reasons.

[Alysson]

But can a host access a volume via the non preferred owner?

[Torsten.]

Let's assume a real SAN:

The preferred owner fails or the SAN connected to the preferred owner fails, the other controller becomes the current owner and owns the disk.

While doing the presentation you present a volumes via the array ports. Usually to all 4 array ports.

But the access via the "non-owner" will not be optimal (slower).

[Alysson]

OK. Thanks for that.