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SCSI bus speed downshifted

New Member

SCSI bus speed downshifted

I'm receiving this error in syslog...

SCSI bus speed downshifted, SCSI port 2

Linux 7.2 on DL380 G4 using a SA 6400 controller connected to an MSA30.

Has anyone seen this error before?

Steven E. Protter
Exalted Contributor

Re: SCSI bus speed downshifted

Shalom SoxFan.

Which Sox? White or Red?

To the issue at hand:

Seems like a connectivity problem on the MSA30 and/or controller.

Check termination, cabling and the hardware health of the card.

See if the MSA30 has any error messages on its front panel.

Steven E Protter
Owner of ISN Corporation
New Member

Re: SCSI bus speed downshifted

Red Sox...

We have confirmed proper termination, cabling and health of the Smart Array 6400 controller. The firmware for the server and 6400 is up to date. The MSA30 is a direct attached SCSI unit with no front panel as in the MSA1000.

The errors, "SCSI bus speed downshifted, SCSI port 2" typically coincide with serious I/O performance degradation. Only fix is to reboot the server. However this isn't always an option as we have 15 servers with identical configuration and are used in a RAIN (Redundant Array of Independent Nodes) for our Avamar-based backup system.
Honored Contributor

Re: SCSI bus speed downshifted

In an MSA30/SA6400 setup, the usual cause of a single drive degradation is usually an impending failure of the drive or ancient firmware in the drive.

Since you have said that it is a RAID setup on a box that is inconvenient to shut down, my advice would be to get a warm backup of your system, then hot-swap the drive out with a new one.