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  • Dynamically rescan LUN’s on SLES

    Posted on February 24th, 2009 ashinn No comments

    I’m sure this is kids play to most people, but I’ve just not done much SAN work with Linux.

    We bought a new EMC CLARiiON CX4-240, and I was just tossing it random LUN’s to do speed & HA tests. When I added a LUN I’d see it in powermt, and I didn’t know what the equivalent of devfsadm was in Linux … SLES to be specific. What can I say, I worked with Solaris way too long.

    The first step is to run: powermt display

    # powermt display
    CLARiiON logical device count=3
    —– Host Bus Adapters ——— —— I/O Paths —– —— Stats ——
    ### HW Path Summary Total Dead IO/Sec Q-IOs Errors
    3 qla2xxx optimal 6 0 – 0 0
    4 qla2xxx optimal 6 0 – 0 0

    Note the 3/4 preceding the HBA’s.

    Now, execute this:

    # echo “- – -” > /sys/class/scsi_host/host3/scan
    # echo “- – -” > /sys/class/scsi_host/host4/scan

    Its my understand this also works on RHEL and others, but YMMV. This is all buried in the PowerPath manual too, but hopefully I’ve saved someone a bit of time.

    Till next time…