linux 测试 io速度

linux 测试 io速度
rm -f test.dat && dd if=/dev/zero of=test.dat
过几秒钟 ctrl+c,可以看到如下输出。
528637+0 records in
528636+0 records out
270661632 bytes (271 MB) copied, 1.03887 seconds, 261 MB/s

下面是 dd命令的帮助。
Usage: dd [OPERAND]…
or: dd OPTION
Copy a file, converting and formatting according to the operands.

bs=BYTES force ibs=BYTES and obs=BYTES
cbs=BYTES convert BYTES bytes at a time
conv=CONVS convert the file as per the comma separated symbol list
count=BLOCKS copy only BLOCKS input blocks
ibs=BYTES read BYTES bytes at a time
if=FILE read from FILE instead of stdin
iflag=FLAGS read as per the comma separated symbol list
obs=BYTES write BYTES bytes at a time
of=FILE write to FILE instead of stdout
oflag=FLAGS write as per the comma separated symbol list
seek=BLOCKS skip BLOCKS obs-sized blocks at start of output
skip=BLOCKS skip BLOCKS ibs-sized blocks at start of input
status=noxfer suppress transfer statistics

BLOCKS and BYTES may be followed by the following multiplicative suffixes:
xM M, c 1, w 2, b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024,
GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y.

Each CONV symbol may be:

ascii from EBCDIC to ASCII
ebcdic from ASCII to EBCDIC
ibm from ASCII to alternate EBCDIC
block pad newline-terminated records with spaces to cbs-size
unblock replace trailing spaces in cbs-size records with newline
lcase change upper case to lower case
nocreat do not create the output file
excl fail if the output file already exists
notrunc do not truncate the output file
ucase change lower case to upper case
swab swap every pair of input bytes
noerror continue after read errors
sync pad every input block with NULs to ibs-size; when used
with block or unblock, pad with spaces rather than NULs
fdatasync physically write output file data before finishing
fsync likewise, but also write metadata

Each FLAG symbol may be:

append append mode (makes sense only for output)
direct use direct I/O for data
dsync use synchronized I/O for data
sync likewise, but also for metadata
nonblock use non-blocking I/O
nofollow do not follow symlinks
noctty do not assign controlling terminal from file

Sending a USR1 signal to a running `dd’ process makes it
print I/O statistics to standard error and then resume copying.

$ dd if=/dev/zero of=/dev/null& pid=$!
$ kill -USR1 $pid; sleep 1; kill $pid
18335302+0 records in
18335302+0 records out
9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s

Options are:

–help display this help and exit
–version output version information and exit

Report bugs to .

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