cabling an autoraid 12H to two hosts

[Marty Hoff]

I'm trying to set up an autoraid system and attach it to two hosts. I know it is possible to do what I would like to do, but I'm having trouble.

I have 2 R-class systems both of which have two Diff SCSI cards that can be used. The autoraid has two controllers. I'd like to set it up so that both hosts are connected to both controllers. However, when I try to do that, the hosts can't see the LUNs that are set up on the autoraid. I believe it may be a problem with termination of the SCSI buses.

Can anyone advise how the cabling should be done to have both hosts see the disks on both buses?

I have HP fast-wide SCSI cables. I also have some in-line terminator cables. I even have some dual-headed HP fast-wide SCSI cables. I have the appropriate terminators as well.

Thanks for any suggestions.

Marty

[Bernhard Mueller]

Marty,

since each AutoRaid controller will then be connected to *two* host bus adapters on a single SCSI bus, you have to make sure the initiator SCSI ids on one host will be different from those of the other. The default for an initiator is always 7. So on one machine you have to set the SCSI ID of the HBA to 6.

You should not use the card to which the internal disks are attached.

Regards,
Bernhard

[Marty Hoff]

Bernhard,

Thanks! I didn't even think of that. How do I go about changing the HBA SCSI ID on one of the two boxes.

Marty

[Marty Hoff]

Just to clarify - I am not using the internal disk controller. I have two additional controllers on each of the R-Class boxes.

Marty

[Bernhard Mueller]

Since that should be the same HSC cards as in the D-class I guess there are dip switches on the card.

So you have to open the box and pulll it out. Can't remember exactly but I would bet there is a label like ID or SCSI ID or similar. Remember the current setting is 7 and you should be able to judge which switches to push into which direction to make it 6.

Regards,
Bernhard

[malvin drakley · Accepted solution]

Marty, the card you have to connect it to will be an A4107A and the switch bank is labelled GP1-0,GP1-1,GP1-2,and GP1-3 so one switch bank should have 0,1 and 2 to the right (with the board facing you and the other should have switches 1 and 2 to the right. You will need a FWD terminator on the X and Y ports on your autoraid. (part number is A1658-62024)
hope this helps a bit more
malvin

[A. Clay Stephenson]

In this case you will NOT terminate at the Disk Array but rather the controllers will be on the ends of the bus. You need to make certain that the terminator resistor pack are inserted in the active sockets and not in the sockets labeled "spare". As mentioned one controller will be left at SCSI ID 7 and the other at the next highest priority, 6.