SCSI bus speed downshifted

[SoxFan]

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]

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.

SEP

[SoxFan]

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.

[Alan_152]

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.