LinuxQuestions.org - how to "defrag" with slow working Ubuntu Linux?

Quote:

Originally Posted by John VV (Post 4840922)

that is a Microsoft concept and problem
the file systems used in linux OS's do not need to be "defraged"

You know I used to think that, but I have found it not to be true.

Try using 'filefrag' to determine the number of extents of files on the filesystem. The fragmentation can get into the thousands of extents and can really slow down performance. There exist a number of scripts and programs to defragment files on Linux (I'm not sure which ones are maintained) and I have also written my own script:

defrag:

Code:

#!/bin/sh

# finds fragmented files



error() # error

{

        echo "ERROR: $1"

        exit 1

}



# make sure we are root

if test ~ != /root

then

        error 'you must be root in order to run this script'

fi



# make sure we have less than 1 argument

if test $# -gt 2

then

  echo "Usage: $(basename $0) option"

  echo 'option can be:'

  echo 'find'

  echo 'defrag [threshold]'

  # fail

  exit 1

fi



# places

dir=/root/.defrag

output="$dir"/output

sorted="$dir"/sorted

defrag="$dir"/defrag

tempdir=/tmp/defrag



# vars

thres=5



if test "$1" = "find"

then

        # generate cleanly

        if test ! -d "$dir"

        then

                rm -f "$dir"

                mkdir "$dir"

        fi

        > "$output"



        # find files in /

        find /bin /etc /home /lib /lib64 /opt /root /sbin /usr /var -type f -print0 | xargs -0 filefrag > "$output"



        # sort

        awk '{printf("%s|%s\n",$(NF - 2),substr($0,1,match($0,/: [0-9]* extents? found/)-1))}' "$output" | sort -n > "$sorted"



        # info

        echo "Ouput written to $output"

        echo "Sorted output written to $sorted"

        echo

        echo "Most fragmented files"

        tail "$sorted"

        echo

elif test "$1" = "defrag"

then

        # $2 must be defined and a number

        if test "$2" != ''

        then

                if echo "$2" | grep '^[0-9]*$'

                then

                        thres="$2"

                fi

        fi

        # generate defrag list

        awk -F'|' -v thres="$thres" '{ if ($1>thres) print $2}' "$sorted" > "$defrag"

        

        # defrag

        echo

        echo "Files to be defragmented:"

        cat "$defrag"

        echo

        echo 'How do you want to defrag these files ?'

        echo '[i]n place (copy to .defrag and move back)'

        echo '[t]emporary directory (default is /tmp/defrag)'

        echo '[n]o defrag, just exit'

        read answer

        case "$answer" in

                i|I)

                        while read line

                        do

                                cp --preserve=all "$line" "$line.defrag" && mv "$line.defrag" "$line"

                        done < "$defrag"

                ;;

                t|T)

                        mkdir "$tempdir" || error "$tempdir exists"

                        while read line

                        do

                                cp --preserve=all "$line" "$tempdir" && mv "$tempdir/$(basename "$line")" "$line"

                        done < "$defrag"

                        rmdir "$tempdir" || error "$tempdir is not empty, check it for files"

                ;;

                n|N)

                        error 'exiting on user input'

                ;;

                *)

                        error 'bad input'

                ;;

        esac

else

        error 'input is not sane'

fi



exit 0

Use at your own risk ! It is provided as-is, no warranties implied.

Typical usage, as root:

Code:

defrag find

defrag defrag