Commands tagged ssd (4)

  • set your ssd disk as a non-rotating medium

    if you still get a permissions error using sudo, then nano the file: sudo nano -w /sys/block/sdb/queue/rotational and change 1 to 0 this thread: http://www.ocztechnologyforum.com/forum/showpost.php?p=369836&postcount=15 says that this will "help the block layer to optimize a few decisions"


    5
    sudo echo 0 > /sys/block/sdb/queue/rotational
    nickleus · 2009-11-27 12:16:17 3
  • Performance tip: compress /usr/

    Periodically run the one-liner above if/when there are significant changes to the files in /usr/ = Before rebooting, add following to /etc/fstab : = /squashed/usr/usr.sfs /squashed/usr/ro squashfs loop,ro 0 0 usr /usr aufs udba=reval,br:/squashed/usr/rw:/squashed/usr/ro 0 0 No need to delete original /usr/ ! (unless you don't care about recovery). Also AuFS does not work with XFS


    4
    [ ! -d /squashed/usr ] && mkdir -p /squashed/usr/{ro,rw} ; mksquashfs /usr /squashed/usr/usr.sfs.new -b 65536 ; mv /squashed/usr/usr.sfs.new /squashed/usr/usr.sfs ; reboot
    mhs · 2014-05-10 06:01:06 0
  • Check if you partition are aligned

    To get most of you HDD/SSD driver you need to make sure you partition are aligned, if not the speed penalty can be up to 50% slower! this simple one liner will check to see if each partition start sector is divided by 512 you need to change sda with your driver if you find the one of your partitions is not aligned use gparted to move the start sector of the partition to be divided of 512 Show Sample Output


    1
    fdisk -l /dev/sda | grep -E sda[0-9]+ | sed s/*// | awk '{printf ("%s %f ",$1,$2/512); if($2%512){ print "BAD" }else {print "Good"} }' | column -t
    The_IceMan_Blog · 2012-05-18 08:34:36 1
  • Check SATA link speed.

    Check SATA controller type. 6.0 Gbps - SATA III 3.0 Gbps - SATA II 1.5 Gbps - SATA I Show Sample Output


    1
    dmesg | grep -i sata | grep 'link up'
    FadeMind · 2013-04-18 15:41:33 0

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swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

List the most recent dates in reverse-chronological order

Command to logout all the users in one command

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