Figure 5: Calculating Open File Table Requirements

A. To use pstat to monitor usage:

# pstat -f | head -1

B. To use crash to monitor usage:

# crash

dumpfile = /dev/kmem, namelist = /sysV68,
outfile = stdout
> file

Output for this command shows the number of currently defined open file entries and the maximum number of entries, which is the SLOT number of the last entry in the table. It is also possible that the list will not be entirely numerical. In that case, you will want to pipe the output of the file subcommand through the command wc -l, so the actual number of table entries can be ascertained. Don't forget to subtract the appropriate number of lines for the header from crash

> file ! wc -l
28
> 

C. The Formula

NFILE = BASE + (number-of-users *
( largest-number-of-files-used )

This calculation gives the minimum number of entries to have configured in the kernel for the open file table.