Conference ssdevo::hsd30_product

295.0. "HSD50/HS0F V5.0 NO QUIESCE-BUS NECESSARY??" by KERNEL::CLARK (STRUGGLING AGAINST GRAVITY...) Wed Apr 09 1997 11:43

    The document "Servicing your storageworks Subsystem" (HSD50 array
    controllers, HSOF version 5.0) indicates on page 260 (Removing Storage
    Devices) that....
    
    "Disk drives may be removed without having to quiesce the device
    bus..."
    
    	There are restrictions mentioned, but in general it would seem that
    it is now possible to remove a drive without quiescing the bus!!!!
    
    Questions:-
    (1) Is it possible to insert a drive without quiescing the bus?
    (Various sections in chapter 4 of the same document suggest/imply that
    you can!!)
    
    (2) Is this feature incorporated in the new code? (Sense power down of
    device, quiesce bus....etc)
    
    (3) How is this likely to behave in the situation where a drive on the
    bus is in the process of flushing WBC?
    
    	A customer has asked these questions and needs to know a few answers
    before he updates his operations staff on re-configuration procedures.
    
          			Dave Clark
    				UK-CSC

    Did I say something wrong?.....It's awful quiet in here!!
    
    				Dave

  Yup... Nobody wants to touch this one ;-.]

  Although you don't have to quiesce the bus you had better make sure that
the drive is no longer ONLINE to the host.  If it is still ONLINE you will
find that there may be data in the cache and you won't like the results.
You have to be real careful to ensure that you don't get burned.  The safe
place to perform this operation is on a drive in the failset.  Those drives
no longer have data in the cache.

  Inserting a drive without quiescing the bus should be safe since it doesn't
have a cache problem.

    Thanks for the feedback.
    
    	Do I get the feeling that we are waiting for the problem calls to
    come in before we can define the guidelines??
    
    				Dave