How to Check File Access (sar -a)

1. Display file access operation statistics with the sar -a command.

   $ sar -a SunOS balmyday 5.10 s10_51 sun4u 03/18/2004 00:00:00 iget/s namei/s dirbk/s 01:00:00 0 3 0 02:00:00 0 3 0 03:00:00 0 3 0 04:00:00 0 3 0 05:00:00 0 3 0 06:00:00 0 3 0 07:00:00 0 3 0 08:00:00 0 3 0 08:20:01 0 3 0 08:40:00 0 3 0 09:00:00 0 3 0 09:20:01 0 10 0 09:40:01 0 1 0 10:00:02 0 5 0 Average 0 4 0

   The following list describes the field names and description of operating system routines that are reported by the sar -a command.

   iget/s

   The number of requests made for inodes that were not in the directory name look-up cache (DNLC).

   namei/s

   The number of file system path searches per second. If namei does not find a directory name in the DNLC, it calls iget to get the inode for either a file or directory. Hence, most igets are the result of DNLC misses.

   dirbk/s

   The number of directory block reads issued per second.

   The larger the reported values for these operating system routines, the more time the kernel is spending to access user files. The amount of time reflects how heavily programs and applications are using the file systems. The -a option is helpful for viewing how disk-dependent an application is.