9333 Reset Program for HA Configuration

ITEM: RTA000071401



I tested a 9333reset Program, which is in the Appendix D.2 of                   
"High Availability Strategies for AIX" (GG24-3684-00), in the                   
twin-tailed configuration of 9333 as follows:                                   
                                                                                
   ---------                        ---------                                   
   | RS/6K |                        | RS/6K |                                   
   | (w/AIX|        =======         | (w/AIX|                                   
   |  V325)|--------|9333-|---------|  V325)|                                   
   ---------        | 501 |         ---------                                   
     CPU-A          =======           CPU-B                                     
                                                                                
I tried to test the following steps:                                            
  1. To vary-on the vg on 9333-501 from CPU-A                                   
  2. To issue '9333reset' from CPU-A                                            
           (i.e. "9333reset /dev/serdasd0 0" )                                 
  3. To vary-on the vg on 9333-501 from CPU-B                                   
But, the step 2 failed with the "error on open.. error no is 13"                
(Error 13 is 'Permission denied').                                              
I changed the forth parameter of 'openx' in that program from                   
'SC_DIAGNOSTIC' to 'SC_FORCED_OPEN', then the above steps worked                
fine.                                                                           
Although I know that the usage of '9333reset' like this is not                  
normal, could you answer the following questions?                               
 Q1. Could you explain the reason why the 'Permission Denied' is                
     displayed in the above step 2?                                             
 Q2. The workaround which I took as above seems to work correct-                
     ly as far as I tested.  If there are any possible problems                 
     or concerns to use such a method, please advice me.                        
                                                                                
                                                                               
ANSWER                                                                          
Q1. The program is meant to be run from the opposite CPU from that which        
    has or had the disk(s) varied on. In your case, this would be from          
    CPU-B. If you run it from CPU-A, you are subject to 2 causes of the         
    EACCES error condition which you got. From the "Error Conditions from       
    Serial DASD Subroutines" article in InfoExplorer, they are:                 
    1) Indicates an attempt was made to open a diagnostic session on a          
       device already opened. (If the vg is varied on on CPU-A when you         
       run this program, both the controller and the disk device have           
       been opened. This is not the case on CPU-B, which is where the           
       program is meant to be run from.)                                        
    2) Indicates an attempt was made to open a diagnostic session on a          
       device whose child devices are already opened. (Similar situation        
       to the above.)                                                           
Q2. Since this program is not officially supported, and especially when        
    used in this way, I cannot give you a definitive answer. However,           
    when you used the SC_FORCED_OPEN parameter, a reset is done before          
    the device is opened. I would think that this would adversely affect        
    any other volume groups defined on disks from the same controller,          
    that are varied on at the time you run this program.                        
                                                                                
S e a r c h - k e y w o r d s:                                                  
9333RESET OPENX PERMISSION REDBOOK                                              
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                               


WWQA: ITEM: RTA000071401 ITEM: RTA000071401
Dated: 02/1995 Category: ITSAIHA6000
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