SCSI bus speed and width reported on the MSL6030 library

[Peter_505]

Server: DL380 G3 or G4 SCSI with the 2 channel U320 controller.

What would cause the bus speed and width to go from WIDE/FAST to NARROW/ASYNCRONOUS?

When the server and library are cold booted it goes back to WIDE/FAST

The U320 controller, SCSI cables and entire MSL 6030 library have been replaced.

We have roughly 400 servers installed and I see this on multiple servers.

[Marino Meloni_1]

When and where are you seeing that the bus is working in Narrow mode?

this may be seen during boot up, when the scsi bus is syncronizing and doing "domain validation", this is a process wher the hba send data over the scsi bus at various speed checking for the echo and trying to validate the highest speed supported in that particular scsi bus, so all the components should support that speed (HBA, scsi cable, scsi ter minator, Drive, and controller)

when the correct speed for this environment is selected, all the communication shoudl run at that speed.

the wide or narrow mode is selected usualy if there is problems on the higher 8 bits of the scsi bus due to bent/broken pin

[Richard Bickers]

Hi Peter. Are you getting this information from an LTT support ticket?

If there are SCSI issues then the drive should also detect them and this should be output in the device analysis section of the ticket. This is also where you'd see warnings about bus speed.

The actual speed detected is also listed under the configuration section.

I'm a little worried that there may be a decode boundary case in LTT that mistakes the negotiated speed. The best way to find out what you've really got is to run the device performance test in LTT and see what transfer rate you get - that's what counts at the end of the day.

What drives/OS are you using?

If you would like to post a ticket we can take a look from the drive perspective.

How long does the negotiation remain fast? Does it drop as soon as you transfer data or does it take a while? That might indicate the quality of the connection.

[Peter_505]

I am seeing this when in hpsmh/Storage. The bus speed and width are shown when you selecte the U320 controller followed by the library.

Frustrating thing is I can't run L&TT because it's a RHEL3 U7 server. Any attempt to do the L&TT hardware scan will result in a kernel panic. For various reasons the server cannot be upgraded to U8 (where L&TT is supported).