Adding D6977A to SAN causes loss of connectivity to JBOD

[Christopher Rupnik]

The topology of my san is

D8602B with win2k (driver 2.0.25.44) and Q2100A with netbsd connected via a D6976A FC hub. The drives in the JBOD are (4) Seagate FC19171FC. Everything so far works fine. I have allocated two drives to the w2k system and one drive to the netbsd system.

Problem starts when I connect the D6977A into the loop. This system is running NT4.0, (driver version 2.10). The orange lights on the FC hub blink, and then all communication is lost. Neither the win2k , netbsd nor the NT4.0 system can see any of the drives. Is there fundamentally something incorrect with this setup? Note: all this is FCAL.

[Eugeny Brychkov]

Christopher,
blinking led of the hub means that LIP (loop initialization primitive) is in progress. As soon as it always blinks, then I guess loop can not finish initializing. Why? Could you please try constructing you loop from connecting only D6977A hba into hub: shutdown and disconnect everything, then connect D6977A to the hub and turn on hub and server with D6977A. In this config, when there's only one device in the 'loop' everything should be ok. Then try adding storage or host devices into loop and see if loop will be stable or not. Try to change hub port location D6977A is connected to.
If all these tests above will fail you probably have bad D6977A card and you have to replace it with D8602B card. I'm not sure if this card has GLM (Gigabit link module, not GBIC) which can be faulty
Eugeny

[Christopher Rupnik]

The problem seems more based towards windows than the cards. I replaced both the HP cards with Compaq (nee DEC KGPSA), and the same situation occurs. Either of the machines can see the drives if that is the only machine on the loop. I am not trying to share disks (two machines accessing same drive) but insteady trying to allocate one drive to one system, and another drive to the other system

Is there a problem putting two windows 2000 (or one windows nt4.0 and one win2k) system on the same FC-AL? Is this not supported?

[Eugeny Brychkov]

In fc-al environment all connected hosts can see all connected targets. So if you'll connect 2 servers then both servers will see same disks and torture you with everytime 'do you want to write signature to this disk'. The solution is to install MS clustering services. But I'm not sure if you can run NT4 and w2k machines in same cluster :o(
This is at least. Unfortunately I can not tell you about hardware compatibility as soon as not familiar with D6976A hub
Eugeny

[Christopher Rupnik]

Finally resolved the issue.
The first step was to disable the removable storage service on the win2k box. The next step was to boot one host at a time and manually find and disable each hard drive you did NOT want on the win2k hosts. After that procedure, the hosts could at least all be on the same FCAL, but not seeing all the disk. To resolve that, I cascaded the D6976A into a more typical A3724A 10 port FC hub. I plugged all the windows machines into that hub, then used an uplink to the D6976A where the hard drives were, and then it all worked as designed. I can see one disk at a time on each hosts, and no conflicts. I supposed the D6976A has some issues, and the A3724A is a better FCAL hub.