problem dual attaching an HA storage enclosure

[Anthony Bowles]

Hi,

I have a couple of workstations (C180's) which both have A2874 FW HVD SCSI controllers.

I'm trying to dual attach them to an HP Storage Enclosure (non-rackmount Jamaica) populated with 4.3GB differential disks.

I've set both A2874 controllers to have different ID's using the onboard dip switches. I've also moved the terminator blocks so as to terminate the internal controllers.

Then I've put the three in a chain, with a cable linking the two buses within the enclosure.

The problem I get is that neither workstation can see any disks. If I detach either of the workstations and put in a terminator the other workstation can then see the disks.

It looks like each controller is failing to provide termination for the other workstation.

Would self-terminating cables help ? Anyone have the part number ?

Cheers,
Anthony

[Steven E. Protter]

Part numbers come from here:

http://partsurfer.hp.com

Question: Are you sure these 4.3 GB disks are LVD disks. If not, that explains why they are not recognized. You can't run SE disks on an LVD controller.

SEP

[Anthony Bowles]

Thanks for the link.

Tbey are differential disks, they're labeled 4.3GB DF.

When I attach the enclosure to just one workstation the disks come up fine so it's definitely the daisy chaining that's causing the problem.

Cheers,
Anthony

[Helen French]

May be it's the SCSI ID of the controllers that clashing each other. You cannot have two controllers on the same SCSI bus with the same SCSI ID. The default ID for controllers is 7.

Check the SCSI ID with 'ioscan -fn' command and make sure both has different SCSI IDs.

[curt larson_1 · Accepted solution]

I've set both A2874 controllers to have different ID's using the onboard dip switches. I've also moved the terminator blocks so as to terminate the internal controllers.

my experience has been that using the internal termination doesn't work all that good with external discs and terminator. I've always found this not too work when singlely attaching a jamaica.

I had to check out a couple of df disks so I put them into a jamaica and the drives work fine. I took a second c200, changed the scsi controller address and attached it to the other end of the jamaica where i disconnected the terminator, and i can still access the drives fine.

the scsi cards are set up for external termination.

at the moment my second system while powered on doesn't seem to have booted, so this might not be totally functional. I'll have get back to you after I get the second system booted. (I have some monitor issues).

[curt larson_1]

well with the external terminators and both systems up doesn't seem to work either. ioscans hang when done from either system

[curt larson_1]

a little extra info from an service guard manual

Online Hardware Maintenance with In-line SCSI Terminator

MC/ServiceGuard allows online SCSI disk controller hardware repairs to all cluster nodes if you use HP's in-line terminator (C2980A) on nodes connected to the end of the shared FW/SCSI bus. The in-line terminator cable is a 0.5 meter extension cable with the terminator on the male end, which connects to the controller card for an external bus. The in-line terminator is used instead of the termination pack that is attached to the controller card and makes it possible to physically disconnect the node from the end of the F/W SCSI bus without breaking the bus's termination. (Nodes attached to the middle of a bus using a Y cable also can be detached from the bus without harm.) When using in-line terminators and Y cables, ensure that all orange-socketed termination packs are removed from the controller cards.


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You cannot use inline terminators with internal FW/SCSI buses on D and K series systems, and you cannot use the inline terminator with single-ended SCSI buses. You must not use an inline terminator to connect a node to a Y cable.

so maybe you need a C2980A inline terminator cable?

[Anthony Bowles]

That was a great set of responses.

It looks like the need for inline terminator cables is understated, although this may not be the same when using supported servers.

I'll pick a couple up of these cables up and see if it helps - taking out the terminator blocks in case it becomes over-terminated.

Many thanks,
Anthony

[curt larson_1]

Anthony, I provided you with some bad info in my previous posts. Because, this wasn't working as I expected, I've done some further testing. And to answer some of your questions:

your stated "I've set both A2874 controllers to have different ID's using the onboard dip switches. I've also moved the terminator blocks so as to terminate the internal controllers.

Then I've put the three in a chain, with a cable linking the two buses within the enclosure.

The problem I get is that neither workstation can see any disks. "

1) I've done the same thing as you have:
I've set both A2874 controllers to have different ID's. I have one at 7, the other at 6

2) I've also moved the terminator blocks so as to terminate the internal controllers.
yes this is how it works. the resistior packs are located like in the attached pic.

3) Then I've put the three in a chain, with a cable linking the two buses within the enclosure. yep me too

4) The problem I get is that neither workstation can see any disks. We differ here, this isn't my problem.

I started one workstation. it sees all the disks just fine using ioscan.

I started the other workstation. it sees all the disks just fine using ioscan and has a couple of disks mounted as file systems.

So, my results, using pretty much your same setup, is that it works.

Being each workstation works seperately, I'd check that the controller id's aren't conflicting and that the scsi cables aren't excessively long, I think the spec is 15m max.

the problem i was having previous when the ioscans didn't work was one controller was terminated internally and the other wasn't.

again a apologize for my previous inaccuraties.

[Anthony Bowles]

That's no problem atall.

I purchased the two inline terminators and inserted them between the existing SCSI cables and the workstation SCSI cards.

I left the terminal blocks as terminating the internal controllers, powered up the workstations and it still didn't work.

So I powered down, removed the internal controllers, powered up and it all works fine now.

Both systems can see all drives and I can just fire one up and there's no problem with a hanging SCSI bus from the other.

Thanks again,
Anthony