According to the manual of "sar" in Unix systems (computerhope.com/unix/usar.htm), it allows to determine the number of accesses to system buffers (lread and lwrite). Thus, we can easily calculate the cache hit ratio of I/Os via the system buffer.

However, "sar" in Linux only measures I/Os to physical devices (as bread and bwrite), instead of those to the system buffer (linux.die.net/man/1/sar)

I need to measure cache hit ratios for I/Os on Linux system buffer, and was wondering if there's a way to use "sar" or any other similar tools to determine such ratios.

Please let me know if you have any clues.

Thank you very much,