Disk Benchmark

Disk Benchmark / Performance / Speed

Write speed

dd 
    if=/dev/zero 
    of=<file> 
    bs=<size>[K|M|G] 
    count=<count>[K|M|G] 
    { conv=fsync | oflag={sync|dsync|direct} }

Option	Description
conv=fsync	Synchronize before finishing
dsync	Synchronized I/O for data
sync	Synchronized I/O for data and meta data
direct	Direct I/O

dd if=/dev/zero of=temp bs=1M count=1K oflag=direct; rm temp

Read speed

Using dd iflag=direct

dd
    if=<file>
    of=/dev/null
    bs=<size>[<unit>]
    [count=<count>[<unit>]]
    iflag=direct

dd if=/dev/sda1 of=/dev/null bs=1M count=1K iflag=direct

Unit	Description
c	1
w	2
b	512
kB	1000
K	1024
MB	1000²
M	1024²
GB	1000³
G	1024³
T	1024⁴
P	1024⁵
E	1024⁶
Z	1024⁷
Y	1024⁸

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Using drop_caches

# Synchronize cached writes to persistent storage
sync

# Free cache
echo 3 > /proc/sys/vm/drop_caches

dd if=<file> of=/dev/null bs=<size>[K|M|G] [count=<count>[K|M|G]]

drop_caches doc

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Read speed test without prior cache

hdparm -t /dev/<device>

Read speed test with buffer

hdparm -T /dev/<device>