| T.R | Title | User | Personal Name
 | Date | Lines | 
|---|
| 2040.1 | And the answer is??? | DYOSW5::WILDER | Does virtual reality get swapped? | Wed May 07 1997 07:10 | 8 | 
|  |     Does the lack of a response mean that pulling the mc cable off IS the
    best way to simulate a memory channel failure? Has anyone done this? Is
    this the BEST way in a hubless environment?
    
    Thanks,
    
    /jim
    
 | 
| 2040.2 | yes | AFW4::CLEMENCE |  | Wed May 07 1997 07:24 | 0 | 
| 2040.3 | Thanks, now, what will happen | DYOSW5::WILDER | Does virtual reality get swapped? | Thu May 08 1997 07:09 | 12 | 
|  |     Thanks.
    
    Now, what should we expect? This will cause a partitioned database
    (since we are running OPS). Therefore, I would expect one node to
    crash. Is there anyway to fresee which node? Will the node running the
    Director survive, or is it a coin toss? Or (heaven forbid) will both
    nodes crash, and let the reboot make the decision on the survivor?
    
    Thanks,
    
    /jim
    
 | 
| 2040.4 |  | KITCHE::schott | Eric R. Schott USG Product Management | Thu May 08 1997 12:50 | 3 | 
|  | Hi
 Do you have quorum disk setup?
 | 
| 2040.5 | Tie-breakers defined | DYOSW5::WILDER | Does virtual reality get swapped? | Fri May 09 1997 07:14 | 18 | 
|  |     Yes, there is a quoru/tie-breaker disk. In fact, there are 3
    tie-breaker disks, one per HSZ pair.
    
    Now, I realize that with 3 disks, the system that sees at least 2 will
    be the winner. My question is, what do we expect to happen? Will the
    winner force the other system to crash? Reboot? What?
    
    If the losing system reboots, what will happen if we re-connect the
    Memory Channel cable while the systems are up?
    
    These are questions I know the customer will be asking, and I would
    like to try to appear knowledgable and have these answers BEFORE they
    ask.
    
    Thanks,
    
    /jim
    
 | 
| 2040.6 | And the result is..... | DYOSW5::WILDER | Does virtual reality get swapped? | Fri May 23 1997 09:51 | 18 | 
|  |     Well, for those of you still wondering, we had to find out what would
    happen at the customer site (I love learning in front of the customer).
    
    When the MC cable was disconnected, the node with the tie-breaker disks
    survived. It forced the other node to panic. After that node crashed,
    it re-booted. When TCR came up, it found the surviving node on the
    network and the SCSI. However, when it discovered that it could NOT see
    it over the memory channel, it displayed the error message and shgut
    itself down to single user mode.
    
    Oracle performed exactly as we had predicted, recovering transactions
    that had not committed on the dead node, while the surviving node only
    paused once briefly.
    
    The customer is impressed!
    
    /jim
    
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