Linux DD command test drive read and write speed

1. DD Command Brief:

if= input file, of= output file, ibs= bytes read at a time, obs= write bytes at a time, bs= set the number of bytes written at one time, skip= skipped BS number, count= copy block number

2. Using/dev/null and/dev/zero

　　1. Treat/dev/null as a "black hole", which is equivalent to a write-only file, and all content written to it will be lost forever

2./dev/zero is a pseudo-file, but it actually produces a continuous stream of NULL

3. Test drive Read and write speed

# # cut into the U-disk directory, test write speed
# dd If=/dev/zero of=./largefile bs=8k count=10000
10000+0 Records in
10000+0 Records out
81920000 bytes ( ) copied, 11.0626 s, 7.4 MB/ s

# # Test Read speed (clear cache)
# sudo sh-c "Sync && echo 3 >/proc/sys/vm/drop_caches"
# dd If=./largefile of=/dev/null bs=8k
8000+0 Records in
8000+0 Records out
65536000 bytes (MB) copied, 2.90366 s, 22.6 MB/s

Source: Internet

Linux DD command test drive read and write speed