The Maximum Value to Open Files Concurrently

ITEM: RTA000069888

I'd like to know about the specification to open files.                         
According to the "limits.h" definition, the maximum number of                   
files that one process can open is 2,000.                                       
Q1. But are there any other limits to open files concurrenly?                   
    Is there global limit as AIX operatins system?                              
Q2. Also, the maxmimum number of processes per user is defined as               
    the attribute of "sys0". Its default is 40, and the maximum value           
    is 131,072.                                                                 
    But what is the maximum value as the whole AIX system?                      
Q3. If no restriction for Q1, and if there is some certain value for            
    Q2, the maximum value for opening files concurrently can be got             
    as follows.                                                                 
         = 2,000 x GLOBAL_MAX_NUM_OF_PROCESSES                                  
    Am I right?                                                                 
Q4. As the result of "sar -v" command, my system returns.."file-sz"             
    value as "596/968".                                                         
    Does 596 mean there are now 596 files opened on whole AIX? Or is            
    it for the files opened by specific user?                                   
    And what does the value "968" mean? ( The "getconf OPEN_MAX"                
    command returns "2000", so I believe the max value per process              
    is 2000.)                                                                   
I fully appreciate your kind help.                                              
Thanks and regards.                                                             
   I will answer your questions in the order they were asked:                   
1) What is the global limit to open files.                                      
   R) The AIX System hardcoded limit of concurrently open files                 
      is 200,000.                                                               
2) What is the maximum value for the number of concurrent processes             
      in AIX?                                                                   
   R) The maximum number of concurrent processes in AIX is 131,072.             
      This vaule is again hardcoded into AIX.                                   
3) If no restriction in Q1 and there is a limit in Q2 then the                  
      maximum number of open files in AIX should be ...                        
   R) Since AIX has a hardcoded limit of 131,072 concurrently open              
      files, this is not a discussible issue.                                   
4) From the output of 'sar -v' the file-sz field returns a value of             
      596/968, what does this mean and is this a system wide or user            
   R) The file-sz field in the 'sar -v' output signifies that system            
      wide there are 596 files open.  The number following that signifies       
      the high water mark for the number of file table entries.  This           
      file entry table is allocated dynamically therefore the number            
      968 signifies a file entry table with 968 entries available, and          
      only 596 entries used.  Since the table is allocated dynamically         
      the number 968 is not the max open files limit but the current            
      size of the open files table.                                             
S e a r c h - k e y w o r d s:                                                  
OPEN FILES SAR PROCESS MAXIMUM                                                  

WWQA: ITEM: RTA000069888 ITEM: RTA000069888
Dated: 07/1996 Category: ITSAI6000GE
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