nfstest_io (1) - Linux Man Pages

nfstest_io: I/O tool


nfstest_io - I/O tool


nfstest_io -d <datadir> [options]


This I/O tool is used to create and manipulate files of different types. The arguments allow running for a specified period of time as well as running multiple processes. Each process modifies a single file at a time and the file name space is different for each process so there are no collisions between two different processes modifying the same file.


show program's version number and exit
-h, --help
show this help message and exit
-d DATADIR, --datadir=DATADIR
Top level directory where files will be created, it will be created if it does not exist
-s SEED, --seed=SEED
Seed to initialized the random number generator [default: automatically generated]
-n NPROCS, --nprocs=NPROCS
Number of processes to use [default: 1]
-r RUNTIME, --runtime=RUNTIME
Run time [default: '0']
-v VERBOSE, --verbose=VERBOSE
Verbose level: none|info|debug|dbg1-7|all [default: 'none']
-e, --exiterr
Exit on first error

Read and write:

Read file percentage [default: 40]
Write file percentage [default: 40]
Read/write file percentage [default: 20]
Random file access percentage [default: 50]
Seconds to delay I/O operations [default: 0.0]
Use direct I/O
Use read and write only, no rename, remove, etc.

File operations:

Create file percentage [default: 5]
Open downgrade percentage [default: 10]
Open file with O_SYNC [default: 20]
Percentage of fsync after write [default: 5]
Rename file percentage [default: 5]
Remove file percentage [default: 5]
Truncate file percentage [default: 5]
Truncate opened file percentage [default: 5]
Create hard link percentage [default: 2]
Create symbolic link percentage [default: 1]
List contents of directory percentage [default: 1]
Lock file percentage [default: 20]
Unlock file percentage [default: 80]
Lock test percentage [default: 50]
Lock full file percentage [default: 50]
Mininum number of files to create before any file operation is executed [default: 10]

File size options:

File size average [default: 1m]
File size standard deviation [default: 256k]
Read block size [default: 64k]
Read block size standard deviation [default: 8k]
Write block size [default: 64k]
Write block size standard deviation [default: 8k]
Size multiplier [default: 1]

Logging options:

Create log file
Create a log file for each process
Log directory [default: '/tmp']


No known bugs.


Jorge Mora (mora [at]