SCSI negotiated speed issue

[solns]

Hi all,
I have a Compaq 8000 with an Adaptec/Compaq Ultra3 64bit\66 SCSI card which uses the compaq driver ADPU160M.SYS connected to a Compaq TL891DLX Tape Library with twin DLT 40/80 drives when I look in Insight Manager under Mass Storage and select the DLT drives they have a negotiated speed of 8bits for both drives and I think this is causing my backups which is using Veritas v8.5 NT SVR by the way, run at a third of the normal capacity of these drives, I have two other Compaq 8000's configured the same or as near as I can get and they have a negotiated speed of 16bits for the 1st DLT and only 8bits for the 2nd, I also understood this SCSI card to be 64bits hence as the SCSI card has two ports externally that they would run at 32bits each, can anyone help me with this problem as I am now nearly bald from rubbing my head so much.

Many Thanks
Steve M.

 

[fraxx]

I'm not quite sure what a "Compaq 8000" is. Maybe some older ProLiant.
A negotiated speed of "8 bits" sounds strange. Maybe you're getting a report that the bus width is 8 bits, which means narrow SCSI.
The TL891DLX is a fast/wide device, so you should get a 16 bit bus width. I'm thinking a termination problem. I assume you've dedicated the SCSI card to the TL891DLX, in which case you must terminate both the TL891DLX and the SCSI card. You must also terminate both hi and low bits, and you might have the SCSI card configured to "low on" "hi off". This means you only have terminated the lower 8 bits and therefore you can only use half the maximum bandwidth.
Check the documentation for the SCSI card on how to check/set the termination.

The fact that the card is 64 bit has nothing to do with SCSI 8 bit or 16 bit (or the theoretical 32 bit*).
The 64 bits is the bus bandwidth to the PCI-bus, which is the other side of the card so to speak.
/charles

*in the specification for SCSI-2, a 32 bit wide SCSI bus is defined, but AFAIK it has never been implemented in any product.

 

[dieselfreak]

There is a known issue with version 6.1.520.202 of the ADPU160M.sys driver

The problem is related to the storage agent, the solution is simply to update to the lastest version from the web ....
For windows 2000

http://www.compaq.com/support/files/server/us/download/14988.html.

For Windows NT4, unfortunately the resoluion so far is to disable the storage agent.




I hope this helps

 

[solns]

Thanks for the replies - COMPAQ also suggested that termination might be an issue. Since posting the question we lost access to one of the paired tape drives and replaced it with a spare, with the same cabling and SCSI terminator.

The server is now running with the new drive having negotiated a 16bit wide i/f and the other is still at 8.
The server in question is actually part of our model environment - the two duplicate servers at customer sites are also running 16 bit for one DLT drive and 8 bit for the other. COMPAQ in the UK have gone into deep-thought mode on this since they state that both drives should have negotiated 16bits - with three servers all with 16+8 they are at a loss to explain it !

I am not clear if the ADPU160M.sys issue would allow one drive to negotiate 16 bit and the other 8 bit - indeed our original drive used to run twice as fast as it did when we noticed the 8bit negotiated i/f, which is why we suspect that a server re-boot led to a lower negotiation bit count, despite retaining the same software/driver configuration.

Thanks again,
Kevin