3

I want to connect an old 12-bay DataStor InfoStation (which is an external storage cabinet) to an LSI MegaRAID SCSI 320-2E host bus adapter and now wonder what bus termination guidelines to follow.

The InfoStation has two HD68 ports but nowhere in the user manual is there any hint at the requirement of termination, nor does it say that it has a built in termination. The manual hints that the two ports represent separate channels and that it is possible to connect the InfoStation to two different hosts, each through each port. Also, the two ports are listed separately in the configuration menus where you set separate LUN Maps and SCSI IDs for each port. There are no "daisy-chain" or "auto-termination" options in the configuration menus and the back panel doesn't say anything about it.

The LSI HBA has two VHDCI ports and the manual explicitly states that there should be a proper termination both when connecting external units and internal units.

Perhaps this is a "point-to-point" setup which doesn't require explicit termination. Is it implicitly understood that the InfoStation is a "point-to-point" unit where the termination is built in to the device? If not, how am I supposed to terminate it when the two ports on the device appear to be on separate SCSI channels?

Darmocle
  • 31
  • 1

1 Answers1

3

Try it and see... Really. If there is no obvious termination guideline or indicator, the device may be terminated internally.

By the time I started working with 68-pin SCSI devices and U320 SCSI, terminators were not necessary as often. The closest thing I have to that, a Compaq/HP MSA30 SCSI disk enclosure, did not require terminators. However, some of the tape drives I have from that era did need the terminators on their second SCSI port.

ewwhite
  • 194,921
  • 91
  • 434
  • 799
  • I may try and it may even work but later give rise to issues. If I run into issues I want to make sure that they are not a result of an improperly terminated bus. The only way to terminate would be to use a pass-through module but I have not yet seen an external HD68 LVD feed-through module in the market. Perhaps it is common practice to build the termination into the cables? – Darmocle May 25 '13 at 13:27
  • ***None of this is common anymore.*** Ultra 320 and parallel SCSI for disk enclosures started to fade away from the marketplace in 2004. You should not need anything special above and beyond your VHDCI->68-pin cables. – ewwhite May 25 '13 at 13:38
  • I have now tried out the set-up and a regular HD68-VHDCI cable is enough to make it work, i.e. no extra termination is needed. There are no issues that I can see and it appears to work normally. However, I would like to see a white paper or similar on what the "best practices" of these things really are before I'm satisfied. Just because it works in this particular case it doesn't mean that it will work in _every_ case. – Darmocle Jun 05 '13 at 12:32