3 Node L-class cluster configuration with SC10's

[Stefan Saliba]

I need to make a cluster setup of 3 L-class servers with 2 SC10's. Enclosed is a diagram of what I want. I know that using this configuration I need to disable the active termination on the SCSI HBA's and instead install inline terminated cables. My question is this. Should I use inline terminated cables everywehere or should some be inline terminated while others not. Should I install terminators at points G and H of the diagram.
And do the BCC's on the SC10 use active termination ?

Can I have anyone's feedback on this setup. Use the cable letters to identify a cable in the reply.

If I left out any info just reply

[Juergen Nagel_1]

In my opinion, your configuration is not supported. Please see the attachment. You should use the second SCSI Controller as alternate path. See the HP configuration guide. There are some options.
Attend: You must change the SCSI ID from the SCSI Controller in the node. You can do this in the boot menu.

[Sanjay_6 · Accepted solution]

Hi Stefan,

You have posted the question at the wrong place. The right place for this question is Catagory HP-UX, Sub category Service Guard.

My suggestion is to modify your layout in this way
L1 --> L Class Server 1
L2 --> L Class Server 2
L3 --> L Class Server 3
S1 ---> SC10 storage System 1
S2 ---> SC10 storage System 2

L1 (SCSI Card 1) ---> S1 (Channel 1) --> L2 (SCSI Card 1) --> S2 (Channel 1) ---> L3 (SCSI Card 1)

L1 (SCSI Card 2) ---> S1 (Channel 2) --> L2 (SCSI Card 2) --> S2 (Channel 2) ---> L3 (SCSI Card 2)

The two paths can provide redundancy for the SCSI controllers and the Channels on the SC10's. You'll need a V-Cable on L2 as per this layout. In effect the SC10's are sitting in between the three L-Class boxes.

Hope this helps.

Thanks

[David Meidam]

You have the right idea. You have a few options when it comes to cabling, V cables are nice, but you could do with out them. However, with 4-v cables, and 8 in-line terminators, you would conserve your ports on the SC's and easily add additional servers w/o re-cabling (more 9's!!). My suggestion would be to put the in-line terminators on the server side, I don't know if that was ever a question, but it seems to me you would be rebooting a server more than you would need to bring the disks down.

[David Meidam]

I don't know what happened to the previous attachment, it is rather crude, but simply displays what I was talking about in my previous response.

[Sanjay_6]

Hi David,

The layout you have suggested is good. But they don't provide and alternate path in case of a controller failure. There is only one path from each server to the each SC10, whereas the one suggested by me had two path and hence you get an alternate path in the case of a controller failure.

Hope this clear the reason i suggested the layour earlier.

thanks