Does HSJ Disks share CI paths (Two Paths)

[Robert V Dixon]

Without access to a CI based machine, I can't verify this, but I believe SDA should be able to give you what you want. Start by choosing a device at the end of the path and issue a
SDA> SHOW DEVICE
and work back thru to the controller.

e.g. SDA>SHOW DEVI DU

It will confirm (again) that both paths are good on PNA and PNB and it might show you traffic counters (or at least give a pointer to the counters).



Of course the performance monitoring tools should also be able to correctly report the traffic on the CI paths but I now suspect that the software has a bug and is incorrectly reporting all the traffic as being on the first path/cable.

Having checked the hardware indicator LED(s) and the view of the hardware from the VMS side, it looks to be the case that both CI cable sets are operating and I think we'd have seen error messages if either path had failed so I believe it is safe to assume that both cable sets are transferring data.

Since the performance monitor is reporting otherwise ( i,e, no traffic on a cable) , I would look to run some high traffic tranfer tests to show that the available bandwidth exceeds 9MB/sec on one CIPCA/star coupler.

Unless there really is a problem with the CI cabling, the CIPCA & start coupler should be able to move about 17.5 MB/sec ( about 140Mb/sec) but of course there may be other bottlenecks ( controllers, disks, ...)

Once you have traffic known to be exceeding 9MB/sec on the CIPCA , you can check the report of that traffic in the performance monitoring software and if it is in accurate you can report the evidence of the bug to the maintenance group.

Its probably worth reporting the bug ( one cable pair carrying 0 traffic) immediately since it is very unlikely that the current traffic is all down one cable pair per CIPCA or star coupler.