fiostat - VxFS file I/O statistics utility

VRTSvxfs

fiostat on [ -o offset] [ -l length] -n nfilerange pathname

fiostat off pathname

fiostat reset pathname

fiostat getconfig pathname

fiostat dump [ -i interval [ -S ] [ -c count] ] -r pathname

The fiostat command prints and resets file and file range I/O statistics, turns on and off file range I/O statistics, and gets file range statistic configuration values. A file range is the portion of the file starting from the offset offset, and ending at the offset equal to offset plus length. The pathname parameter can be the pathname of a regular file or a QIO file. The file name extension ::cdev:vxfs: is required for a QIO file.

The fiostat command reads file-level I/O statistics for the specified file and prints the statistics to standard output. If file range statistics are turned on, fiostat reads and prints statistics for the file ranges. These statistics show I/O activity since the file’s last close or since the previous statistics reset.

on	Turns on file range statistics for the specified file. If it is already on, current statistics are reset to zero and the configuration is set to the specified values.
off	Turns off file range statistics for the specified file. No action is taken if the file range statistics are already turned off.
reset	Resets statistics to zero.
getconfig	Prints the current configuration values, offset, length, and nfilerange, to standard output if file range statistics are turned on. When file range statistics are turned off, fiostat prints zeroes.
dump	Prints file statistics for the specified file to standard output. If file range statistics are turned on, fiostat prints the statistics to standard output.

-c count	The fiostat command stops after printing statistics count times.
-i interval	Prints current I/O statistics every interval seconds.
-l length	Specifies the total length of file ranges in bytes. The length can be specified in kilobytes, megabytes, gigabytes, or terabytes by appending k, m, g, or t. The default length is the file’s current size.
-o offset	Specifies the file offset in bytes where the first file range starts. The offset can be specified in kilobytes, megabytes, gigabytes, or terabytes by appending k, m, g, or t. The default offset is zero.
-n nfilerange
	Specifies the number of file ranges to monitor. The number must be a non-zero value less than 1024. 1024 is the maximum number of file ranges allowed per file.
-r	Resets statistics to zero after each print.
-S	Displays statistics for each interval. Otherwise, the fiostat command displays the accumulated statistics for the entire time interval.

I/O statistics are printed in a single line output record preceded by the file’s name, the current local time on the system, the time when statistics were reset last, and two header lines. The output line consists of blank-separated fields for the object type (file or file range), and statistics on read and write operations:

o	Number of read operations
o	Number of write operations
o	Number of bytes read
o	Number of bytes written
o	Average time spent on read operations
o	Average time spent on write operations

File range statistics do not include average time spent on read and write operations.

The following is sample output of a file-level-only statistics dump:

File Name: /mnt/foo
Current time: Wed 28 Sep 2005 01:08:33 PM PDT
Reset time:   Wed 28 Sep 2005 01:06:33 PM PDT
FILE/SUBFILE OPERATIONS  BYTES       AVG TIME(ms)
             READ WRITE  READ WRITE  READ   WRITE


file         341  348   34926 35699  4.1    4.5

The following is sample output of a file and file range statistics dump:

File Name: /mnt/foo
Current time: Wed 28 Sep 2005 01:08:33 PM PDT
Reset time:   Wed 28 Sep 2005 01:06:33 PM PDT
FILE/SUBFILE OPERATIONS  BYTES       AVG TIME(ms)
             READ WRITE  READ WRITE  READ   WRITE


file         341  348   34926 35699  4.1    4.5
filerange1   27   24    2780  2434   
filerange2   27   28    2744  2813   
filerange3   27   28    2767  2808   
filerange4   25   26    2552  2634   

If the -i interval option is supplied, statistics are prefaced with two time stamps showing the current local time on the system and when statistics were reset last.

The following is sample output of a file and file range statistics dump with -i 3 -c 3 specified:

File Name: /mnt/foo
FILE/SUBFILE OPERATIONS  BYTES       AVG TIME(ms)
             READ WRITE  READ WRITE  READ   WRITE


Current time: Wed 28 Sep 2005 12:56:40 PM PDT
Reset time:   Wed 28 Sep 2005 12:51:50 PM PDT
file         297  301   30426 30918  4.1    4.5  
filerange1   24   19    2503  1984   
filerange2   24   23    2447  2398   
filerange3   24   24    2439  2467   
filerange4   21   22    2122  2293
Current time: Wed 28 Sep 2005 12:56:45 PM PDT
Reset time:   Wed 28 Sep 2005 12:51:50 PM PDT
file         322  324   33074 33746  4.1  4.5  
filerange1   26   22    2677  2204   
filerange2   26   26    2626  2664   
filerange3   26   26    2680  2695   
filerange4   23   24    2368  2490   
Current time: Wed 28 Sep 2005 12:56:50 PM PDT
Reset time:   Wed 28 Sep 2005 12:51:50 PM PDT
file         341  348   34926 35699  4.1    4.5
filerange1   27   24    2780  2434  
filerange2   27   28    2744  2813  
filerange3   27   28    2767  2808  
filerange4   25   26    2552  2634  

fiostat exits with a non-zero status if the attempted operation fails. A non-zero exit code is not a complete indicator of the problems encountered, but rather denotes the first condition that prevented further execution of the command.

To display statistics for file /mnt/foo, which does not have file range statistics turned on:

# fiostat dump /mnt/foo

To turn on file range statistics for file /mnt/foo and monitor the file from offset 1024 to offset 1024+8129=9153 in 10 file ranges:

# fiostat on -o 1024 -l 8129 -n 10 /mnt/foo

To display statistics for file /mnt/foo 8 times at 5-second interval:

fiostat dump -i 5 -c 8 /mnt/foo

vxfs_fiostats_dump(3), vxfs_fiostats_getconfig(3), vxfs_fiostats_set(3)