How to test disk speed in Linux

To assess the speed of your disks in Linux, you can utilize benchmark tools, conduct I/O operations using standard tools, and gauge overall disk performance based on the time required for these tools to read or write files onto the disk.

Two commonly used command-line tools for this purpose in Linux are hdparm and dd. hdparm may not be pre-installed in most Linux distributions and might need to be installed first, while dd comes pre-installed and is ready for use. You can easily install hdparm through your distribution's default package manager repository.

Both are command-line tools and work for various storage devices, such as magnetic or solid-state drives.

1. Open the terminal.
2. Install the hdparm package using your distribution's package manager.

   $ sudo apt update && sudo apt install --assume-yes hdparm # Ubuntu and Debian derivatives

3. Display a list of available hard drives in the system.

   $ lsblk
   NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
   loop0    7:0    0  55.4M  1 loop /snap/core18/1932
   loop1    7:1    0  55.4M  1 loop /snap/core18/1944
   loop2    7:2    0 217.9M  1 loop /snap/gnome-3-34-1804/60
   loop3    7:3    0   219M  1 loop /snap/gnome-3-34-1804/66
   loop4    7:4    0    51M  1 loop /snap/snap-store/498
   loop5    7:5    0  64.8M  1 loop /snap/gtk-common-themes/1514
   loop6    7:6    0  62.1M  1 loop /snap/gtk-common-themes/1506
   loop7    7:7    0  31.1M  1 loop /snap/snapd/10492
   loop8    7:8    0    51M  1 loop /snap/snap-store/518
   loop9    7:9    0  31.1M  1 loop /snap/snapd/10707
   sda      8:0    0    20G  0 disk 
   ├─sda1   8:1    0     1M  0 part 
   ├─sda2   8:2    0   513M  0 part /boot/efi
   └─sda3   8:3    0  19.5G  0 part /
   sr0     11:0    1  1024M  0 rom

4. Execute a benchmark test on the selected disk using hdparm.

   $ sudo hdparm -tT /dev/sda
   
   /dev/sda:
    Timing cached reads:   27522 MB in  2.00 seconds = 13783.98 MB/sec
    Timing buffered disk reads: 1976 MB in  3.00 seconds = 658.03 MB/sec

5. Run hdparm again with the direct option to bypass the disk cache and measure raw disk performance.

   $ sudo hdparm -tT --direct /dev/sda
   
   /dev/sda:
    Timing O_DIRECT cached reads:   14996 MB in  2.00 seconds = 7507.46 MB/sec
    Timing O_DIRECT disk reads: 5724 MB in  3.00 seconds = 1907.99 MB/sec

   More options for hdparm:

   $ hdparm -h
   
   hdparm - get/set hard disk parameters - version v9.58, by Mark Lord.
   
   Usage:  hdparm  [options] [device ...]
   
   Options:
    -a   Get/set fs readahead
    -A   Get/set the drive look-ahead flag (0/1)
    -b   Get/set bus state (0 == off, 1 == on, 2 == tristate)
    -B   Set Advanced Power Management setting (1-255)
    -c   Get/set IDE 32-bit IO setting
    -C   Check drive power mode status
    -d   Get/set using_dma flag
    -D   Enable/disable drive defect management
    -E   Set cd/dvd drive speed
    -f   Flush buffer cache for device on exit
    -F   Flush drive write cache
    -g   Display drive geometry
    -h   Display terse usage information
    -H   Read temperature from drive (Hitachi only)
    -i   Display drive identification
    -I   Detailed/current information directly from drive
    -J   Get/set Western DIgital "Idle3" timeout for a WDC "Green" drive (DANGEROUS)
    -k   Get/set keep_settings_over_reset flag (0/1)
    -K   Set drive keep_features_over_reset flag (0/1)
    -L   Set drive doorlock (0/1) (removable harddisks only)
    -m   Get/set multiple sector count
    -M   Get/set acoustic management (0-254, 128: quiet, 254: fast)
    -n   Get/set ignore-write-errors flag (0/1)
    -N   Get/set max visible number of sectors (HPA) (VERY DANGEROUS)
    -p   Set PIO mode on IDE interface chipset (0,1,2,3,4,...)
    -P   Set drive prefetch count
    -q   Change next setting quietly
    -Q   Get/set DMA queue_depth (if supported)
    -r   Get/set device readonly flag (DANGEROUS to set)
    -R   Get/set device write-read-verify flag
    -s   Set power-up in standby flag (0/1) (DANGEROUS)
    -S   Set standby (spindown) timeout
    -t   Perform device read timings
    -T   Perform cache read timings
    -u   Get/set unmaskirq flag (0/1)
    -U   Obsolete
    -v   Use defaults; same as -acdgkmur for IDE drives
    -V   Display program version and exit immediately
    -w   Perform device reset (DANGEROUS)
    -W   Get/set drive write-caching flag (0/1)
    -x   Obsolete
    -X   Set IDE xfer mode (DANGEROUS)
    -y   Put drive in standby mode
    -Y   Put drive to sleep
    -z   Re-read partition table
    -Z   Disable Seagate auto-powersaving mode
    --dco-freeze      Freeze/lock current device configuration until next power cycle
    --dco-identify    Read/dump device configuration identify data
    --dco-restore     Reset device configuration back to factory defaults
    --dco-setmax      Use DCO to set maximum addressable sectors
    --direct          Use O_DIRECT to bypass page cache for timings
    --drq-hsm-error   Crash system with a "stuck DRQ" error (VERY DANGEROUS)
    --fallocate       Create a file without writing data to disk
    --fibmap          Show device extents (and fragmentation) for a file
    --fwdownload            Download firmware file to drive (EXTREMELY DANGEROUS)
    --fwdownload-mode3      Download firmware using min-size segments (EXTREMELY DANGEROUS)
    --fwdownload-mode3-max  Download firmware using max-size segments (EXTREMELY DANGEROUS)
    --fwdownload-mode7      Download firmware using a single segment (EXTREMELY DANGEROUS)
    --fwdownload-modee      Download firmware using mode E (min-size segments) (EXTREMELY DANGEROUS)
    --fwdownload-modee-max  Download firmware using mode E (max-size segments) (EXTREMELY DANGEROUS)
    --idle-immediate  Idle drive immediately
    --idle-unload     Idle immediately and unload heads
    --Iraw filename   Write raw binary identify data to the specfied file
    --Istdin          Read identify data from stdin as ASCII hex
    --Istdout         Write identify data to stdout as ASCII hex
    --make-bad-sector Deliberately corrupt a sector directly on the media (VERY DANGEROUS)
    --offset          use with -t, to begin timings at given offset (in GiB) from start of drive
    --prefer-ata12    Use 12-byte (instead of 16-byte) SAT commands when possible
    --read-sector     Read and dump (in hex) a sector directly from the media
    --repair-sector   Alias for the --write-sector option (VERY DANGEROUS)
    --sanitize-antifreeze-lock  Block sanitize-freeze-lock command until next power cycle
    --sanitize-block-erase      Start block erase operation
    --sanitize-crypto-scramble  Change the internal encryption keys that used for used data
    --sanitize-freeze-lock      Lock drive's sanitize features until next power cycle
    --sanitize-overwrite  PATTERN  Overwrite the internal media with constant PATTERN
    --sanitize-status           Show sanitize status information
    --security-help             Display help for ATA security commands
    --set-sector-size           Change logical sector size of drive
    --trim-sector-ranges        Tell SSD firmware to discard unneeded data sectors: lba:count ..
    --trim-sector-ranges-stdin  Same as above, but reads lba:count pairs from stdin
    --verbose                   Display extra diagnostics from some commands
    --write-sector              Repair/overwrite a (possibly bad) sector directly on the media (VERY DANGEROUS)

   Related: hdparm(8) - Linux man page

6. Use dd to create a file to evaluate disk write speed.

   $ sudo dd if=/dev/zero of=benchmark.img bs=1G count=5 status=progress
   5368709120 bytes (5.4 GB, 5.0 GiB) copied, 4 s, 1.2 GB/s
   5+0 records in
   5+0 records out
   5368709120 bytes (5.4 GB, 5.0 GiB) copied, 4.36816 s, 1.2 GB/s

7. Remove the temporary file generated by dd.

   $ rm benchmark.img

   More options for dd:

   $ dd --help
   Usage: dd [OPERAND]...
     or:  dd OPTION
   Copy a file, converting and formatting according to the operands.
   
     bs=BYTES        read and write up to BYTES bytes at a time (default: 512);
                     overrides ibs and obs
     cbs=BYTES       convert BYTES bytes at a time
     conv=CONVS      convert the file as per the comma separated symbol list
     count=N         copy only N input blocks
     ibs=BYTES       read up to BYTES bytes at a time (default: 512)
     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 (default: 512)
     of=FILE         write to FILE instead of stdout
     oflag=FLAGS     write as per the comma separated symbol list
     seek=N          skip N obs-sized blocks at start of output
     skip=N          skip N ibs-sized blocks at start of input
     status=LEVEL    The LEVEL of information to print to stderr;
                     'none' suppresses everything but error messages,
                     'noxfer' suppresses the final transfer statistics,
                     'progress' shows periodic transfer statistics
   
   N and BYTES may be followed by the following multiplicative suffixes:
   c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, xM=M,
   GB=1000*1000*1000, G=1024*1024*1024, and so on for T, P, E, Z, Y.
   Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
   
   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
     ucase     change lower case to upper case
     sparse    try to seek rather than write all-NUL output blocks
     swab      swap every pair of input bytes
     sync      pad every input block with NULs to ibs-size; when used
               with block or unblock, pad with spaces rather than NULs
     excl      fail if the output file already exists
     nocreat   do not create the output file
     notrunc   do not truncate the output file
     noerror   continue after read errors
     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; conv=notrunc suggested)
     direct    use direct I/O for data
     directory  fail unless a directory
     dsync     use synchronized I/O for data
     sync      likewise, but also for metadata
     fullblock  accumulate full blocks of input (iflag only)
     nonblock  use non-blocking I/O
     noatime   do not update access time
     nocache   Request to drop cache.  See also oflag=sync
     noctty    do not assign controlling terminal from file
     nofollow  do not follow symlinks
     count_bytes  treat 'count=N' as a byte count (iflag only)
     skip_bytes  treat 'skip=N' as a byte count (iflag only)
     seek_bytes  treat 'seek=N' as a byte count (oflag only)
   
   Sending a USR1 signal to a running 'dd' process makes it
   print I/O statistics to standard error and then resume copying.
   
   Options are:
   
         --help     display this help and exit
         --version  output version information and exit
   
   GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
   Full documentation <https://www.gnu.org/software/coreutils/dd>
   or available locally via: info '(coreutils) dd invocation'

   Related: dd(1) - Linux man page