PowerPath Failure...

Posted on 2006-05-17
Last Modified: 2013-01-18
   I have a Clariion cx700. PowerPath on my exchange server reported the errors below. We have a single port HBA and configured for failover. PowerPath Monitor reports pathname "c4t0d1" as failed, "c4t0d0" as optimal. Under "disk's", it shows "Disk 006" and "Dev ???". Did a drive die? The switches seem ok.

Event Log errors:

1:  Path Bus 4 Tgt 0 Lun 1 to APM00052803117 is dead.

2: The device 'DGC RAID 5 SCSI Disk Device' (SCSI\Disk&Ven_DGC&Prod_RAID_5&Rev_0219\4&b5496fb&0&001) disappeared from the system without first being prepared for removal.


Question by:sudipmis
    LVL 30

    Expert Comment

    by:Duncan Meyers
    PowerPath is complaining because a LUN has been removed from the Exchange server storage group. To fix this:
    Open Computer Management, go to Device Manager and do a scan for hardware changes.
    Open a command prompt. path to C:\Program Files\EMC\PowerPath and run:
    powermt remove dev=all
    This will remove the paths to the missing LUN and PowerPath will stop complaining.

    However, if the LUN was not removed on purpose, then we have a different issue happening. If the LUN was not removed administratively then the most likely cause for the issue is bad FC switch zoning or a bad FC cable - and this should be addressed first.
    LVL 6

    Expert Comment

    What you first need to do is check for a trespassed LUN.  Since you have a single HBA, then you are probably using PowerPath basic--That could mean that the LUN could have trespassed to the other SP, and you are not zoned to that SP's port.

    Check your paths with:

    powermt display every=5

    The easiest thing to do first is to see if the LUN just went offline and then online again (fabric event.)

    powermt restore
    powermt config
    powermt save

    If that doesn't fix it, then go into Navisphere Manager and select "Trespassed LUN Status" from the menu.  Give it a few seconds to populate.  If your particular LUN has trespassed, then  you need to trespass it back, and then restore the PowerPath config just to be safe.
    LVL 30

    Expert Comment

    by:Duncan Meyers
    With respect, if the LUN was trespassed, then PowerPath would report that it could see the LUN - it wouldn't display "Dev ???". This is either a break in connectivity or someone's gone and removed the LUN from the storage group...

    Author Comment

       There are no trespassed lun's.
    LVL 30

    Accepted Solution

    OK - then the likely cause is that your storage administrator has removed a LUN from the storage group for your Exchange server. The LUN could be a normal LUN for data or a SnapView snapshot or clone mounted on the Exchange server for backup or testing and then later destroyed. Either way, the instructions given in my first post will clear the error.

    Assisted Solution

    If the path is dead, I would run "powermt check" to remove it. It'll prompt for removal of only the dead paths. Running powermt remove dev=all may cause a problem if your app is still accessing any of the other hdiskpower devices.

    Expert Comment

    After running powermt check it prompts for y, and when I select y it goes back to the command prompt.  I open the admin console and it's still showing dead. Any tips on fixing?

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