IOSTATS(4) IOSTATS(4)
NAME
iostats - file system to measure I/O
SYNOPSIS
iostats [ -d ] [ -f dbfile ] cmd [ args... ]
DESCRIPTION
Iostats is a file server that interposes itself between a
program and a copy of the current name space, which allows
it to gather statistics of file system use at the level of
the file system protocol of intro(5). When the 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-
actions.
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.
The -d option causes iostats to write a debugging log to
dbfile (default: iostats.out) that records all protocol mes-
sages.
EXAMPLE
Display summary of file I/O incurred by ls(1):
iostats ls
Start a new shell, displaying all Styx traffic caused by the
shell or its children:
iostats -df /fd/1 sh
SOURCE
/appl/cmd/iostats.b
BUGS
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.
Page 1 Plan 9 (printed 12/22/24)
IOSTATS(4) IOSTATS(4)
Cannot monitor standard input or output.
Page 2 Plan 9 (printed 12/22/24)