Testing disk speed in Linux is essential for evaluating the performance of your storage devices. You can use command-line tools to measure both read and write speeds. Tools like hdparm and dd are commonly used for this purpose on Linux systems.

Installing hdparm may be necessary as it is not always included by default in many Linux distributions. It allows you to measure raw disk performance by bypassing the disk cache. Dd, which is usually pre-installed, offers a straightforward method for testing write speeds by copying data.

These tools help you understand your disk's performance, identify issues, and ensure your system's storage is functioning properly. Follow the steps below to perform a comprehensive disk speed test.

Steps to benchmark disk speed in Linux:

  1. Open the terminal on your Linux system.
  2. Install the hdparm package using your distribution's package manager if it's not installed.
    $ sudo apt update && sudo apt install --assume-yes hdparm # Ubuntu and Debian derivatives
  3. List all available disks to identify the target disk for testing.
    $ 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. Run hdparm to benchmark the disk's cached and buffered read speeds.
    $ 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. Use the direct option in hdparm to bypass the disk cache and measure raw 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)
  6. Create a test file using dd to evaluate the write speed of the disk.
    $ 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 test file after the benchmark is completed.
    $ 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'
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