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IOSTATS(4)                 Kernel Interfaces Manual                 IOSTATS(4)

       iostats - file system to measure I/O

       iostats cmd [ args...  ]

       Iostats  is  a  user-level file server that interposes itself between a
       program and the regular file server, which allows it to gather  statis-
       tics  of  file system use at the level of the Plan 9 file system proto-
       col, 9P.  After a program exits a report is printed on standard error.

       The report consists of three sections.  The first section  reports  the
       amount  of user data in read and write messages sent by the program and
       the average rate at which the data was transferred.  The protocol  line
       reports  the  amount of data sent as message headers, that is, protocol
       overhead.  The rpc line reports the total number of file system  trans-

       The  second section gives the number of messages, the fastest, slowest,
       and average turn around time and the amount of data involved with  each
       9P  message type.  The final section gives an I/O summary for each file
       used by the program in terms of opens, reads and writes.


       Poor clock resolution means that large amounts of I/O must be  done  to
       get accurate rate figures.

       Can be fooled by programs that do fresh mounts outside its purview.