Mon 23 Feb

Dell PowerEdge T300 SAS RAID and FreeBSD

I spent a couple hours tonight tackling this problem so I thought I'd post a solution here in case anyone else runs into it.

Scenario: Performed a clean install of FreeBSD7.1-RELEASE on a Dell PowerEdge T300 server with a SAS RAID controller, which completed without errors. After rebooting and beginning to install packages, I started seeing the following error: mpt0: QUEUE FULL EVENT: Bus 0x00 Target 0x00 Depth 120.

Solution: Searching online indicated that the problem was with support for Tagged Command Queuing in the mpt driver. The output of camcontrol was:

skipper# camcontrol tags da0 -v (pass0:mpt0:0:0:0): dev_openings  255 (pass0:mpt0:0:0:0): dev_active    0 (pass0:mpt0:0:0:0): devq_openings 255 (pass0:mpt0:0:0:0): devq_queued   0 (pass0:mpt0:0:0:0): held          0 (pass0:mpt0:0:0:0): mintags       2 (pass0:mpt0:0:0:0): maxtags       255

I then entered:

skipper# camcontrol tags da0 -N 119 (pass0:mpt0:0:0:0): dev_openings  119 (pass0:mpt0:0:0:0): dev_active    0 (pass0:mpt0:0:0:0): devq_openings 119 (pass0:mpt0:0:0:0): devq_queued   0 (pass0:mpt0:0:0:0): held          0 (pass0:mpt0:0:0:0): mintags       2 (pass0:mpt0:0:0:0): maxtags       255

This second command limited the size of the queue to 119, preventing the error I had seen before. To ensure that this problem wouldn't come up in the future, I added the following line to /etc/rc.local

# Set the devq_openings to 119 to prevent problems with SAS controller camcontrol tags da0 -N 119

Doing this runs the command at every boot, preventing the problem from creeping up in the future.

Additional Related Resources: http://www.zulustips.com/2007/09/06/mpt0-queue-full-event-on-dell-sas-5ir.html http://www.nabble.com/mpt-errors-QUEUE-FULL-EVENT,-freebsd-7.0-on-dell-1950-td20019090.html

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