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.
GLOBAL_MAX_NUM_OF_OPENING_FILES
= 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.
ANSWER
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
value?
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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