Performance script (dangerous)

Lontronics · 2007-04-15 21:46:34

I have posted another topic about a quiet harddisk and better performance.
These settings are part of a script I am using at boot and shutdown.

The script is copying my home directory to a ramdisk, the same is done with /tmp.
This is ofcourse only possible when you have a separate /data directory, and not only a $USER where all your stuff is stored.
The result;
- almost no harddisk writes when browsing, reading mail, editing etc...
- almost quiet system
- better performance because most things are done from ram

Disadvantages:
- when your system is crashing, your changes are lost
- you do need more ram (advice 1G or more)
- your system is not standard anymore.

Before using the script, please try to understand what I am doing!

BTW; it is necessarry that the users are added to the group audio in /etc/group, because I am using that group to find out which users are available.

Here is the script (changes mentioned some posts below are added):

#!/bin/sh
#
# Performance script
# Maintainer: Lontronics, info@lontronics.nl
# Last modified: april 16th, 2007

action_start() {
  #
  # Change interval to 10 minutes for pdflush:
  #
  echo 60000 > /proc/sys/vm/dirty_expire_centisecs

  # Let the harddisk spin down when not used for X * 5 seconds
  # For example 12 will give a standby time of 24*5=120 seconds
  # Also set read ahead to on

  if [ -x /sbin/hdparm ]; then
    /sbin/hdparm -S 24 -A 1 /dev/sda
  fi
    
  #
  # Clean ramdisk directory and mount ramdisk for writing temporary information
  #
  if [ -d /mnt/ramdisk0 ]; then
    rm -rf /mnt/ramdisk0/* > /dev/null
  else
    mkdir /mnt/ramdisk0
  fi
  mount -t tmpfs tmpfs /mnt/ramdisk0

  #
  # Check tmp directory...
  #
  if [ ! -d /tmp ]; then
    rm -rf /tmp
    mkdir /tmp
    chmod 777 /tmp
  fi

  #
  # Find available users and take action...
  # We take the audio group in /etc/group, but you can take every group which is containing all normal users
  #
  NAME=($(grep ^audio /etc/group | cut -d: -f4 | tr "," " "))
  count=0
  while [ "x${NAME[count]}" != "x" ]
  do
    #
    # If no user directory then extract the backup when available.
    #
    if [ ! -d /home/${NAME[$count]} ]; then
      rm -rf /home/${NAME[$count]}
      mkdir /home/${NAME[$count]}
      chown -R ${NAME[$count]} /home/${NAME[$count]}
      if [ -f /home/${NAME[$count]}.tar.gz ]; then
        tar zPxvf /home/${NAME[$count]}.tar.gz --directory=/ > /dev/null
        if [ -d /home/${NAME[$count]} ]; then
          echo ""
          echo "WARNING:"
          echo "Extracted backup to /home/${NAME[$count]}"
          echo "It is possible some data is lost..."
          rm -rf /home/${NAME[$count]}.tar.gz
        else
          echo ""
          echo "ERROR:"
          echo "Error occured when extracting files from backup."
          echo "Check backup with name /home/${NAME[$count]}.tar.gz and try to extract it yourself"
          echo "with the command tar zxvf /home/${NAME[$count]}.tar.gz --directory=/"
          echo "New but empty user directory for user ${NAME[$count]} made"
        fi
      else
        echo ""
        echo "ERROR:"
        echo "Unfortunately there seems no backup available."
        echo "New but empty user directory for user ${NAME[$count]} made"
      fi
    fi  

    #
    # Make backup of user directory for when things are going wrong
    #
    tar -cPpz --file=/home/${NAME[$count]}.tar.gz /home/${NAME[$count]} > /dev/null

    #
    # Copy home directory information to the ramdisk for usage
    #
    mv /home/${NAME[$count]} /mnt/ramdisk0
    ln -s /mnt/ramdisk0/${NAME[$count]} /home/${NAME[$count]}

    echo "${NAME[$count]}"
    count=$(( $count + 1 ))
  done

  #
  # Copy tmp directory information to the ramdisk for usage
  #
  mv /tmp /mnt/ramdisk0/tmp
  ln -s /mnt/ramdisk0/tmp /tmp

  #
  # Output
  #
  echo "Performance script started"
  echo "Do not forget to run performance stop before shutdown,"
  echo "otherwise it is possible you will loose your data!"
}

action_stop() {
  ERROR=0
  #
  # Change interval for pdflush to normal:
  #
  echo 500 > /proc/sys/vm/dirty_expire_centisecs

  # Disable standby (spindown)
  if [ -x /sbin/hdparm ]; then
    /sbin/hdparm -S 0 /dev/sda
  fi

  #
  # Find available users and take action...
  # We take the audio group in /etc/group, but you can take every group which is containing all normal users
  #
  NAME=($(grep ^audio /etc/group | cut -d: -f4 | tr "," " "))
  count=0
  while [ "x${NAME[count]}" != "x" ]
  do
    #
    # If temporary user directory available then...
    #
    if [ -d /mnt/ramdisk0/${NAME[count]} ]; then
      #
      # Copy ramdisk information to real directory
      #
      rm -rf /home/${NAME[count]}
      mv /mnt/ramdisk0/${NAME[count]} /home/${NAME[count]}
      rm -rf /home/${NAME[count]}.tar.gz
    else
      ERROR=1
      echo ""
      echo "ERROR:"
      echo "The temporary user directory seems not to be available on the ramdisk, probably the performance script was not running"
      echo "Therefor the following actions are not performed:"
      echo "- /home/${NAME[count]} is not replaced"
      echo "- /mnt/ramdisk0 is not unmounted"
      echo "Please check if everything is okay"
    fi
    count=$(( $count + 1 ))
  done

  #
  # If tmp directory on ramdisk is available then...
  #
  if [ -d /mnt/ramdisk0/tmp ]; then
    rm -rf /tmp
    rm -rf /mnt/ramdisk0/tmp/*
    mv /mnt/ramdisk0/tmp /tmp
  else
    ERROR=1
    echo ""
    echo "ERROR:"
    echo "The tmp directory seems not to be available on the ramdisk, probably the performance script was not running"
    echo "Therefor the following actions are not performed:"
    echo "- /tmp is not replaced"
    echo "- /mnt/ramdisk0 is not unmounted"
    echo "Please check if everything is okay"
  fi

  #
  # If no errors occured unmount the ramdisk to free memory
  #
  if [ $ERROR = 0 ]; then
    umount -f /mnt/ramdisk0 2> /dev/null
    rm -rf /mnt/ramdisk0 2> /dev/null
  fi

  #
  # Output
  #
  echo "Performance script stopped"
}

case "$1" in
'start')
  action_start
  ;;
'stop')
  action_stop
  ;;
*)
  echo "usage $0 start|stop"
esac

To use the script:

in /etc/rc.sysinit find:

stat_busy "Removing Leftover Files"
/bin/rm -f /etc/nologin &>/dev/null
/bin/rm -f /etc/shutdownpid &>/dev/null

just above add:

# Activate the performance script
if [ -x /data/scripts/performance ]; then
  /data/scripts/performance start
fi

Where ofcourse /data/scripts/performance is my path of the performance script, but you have to change this to where you have saved the script

in /etc/rc.shutdown find:

# avoid NIS hanging syslog-ng on shutdown by unsetting the domainname
if [ -x /bin/domainname ]; then
    /bin/domainname ""

just above add:

# Stop the performance script
if [ -x /data/scripts/performance ]; then
  /data/scripts/performance stop
fi

Where ofcourse /data/scripts/performance is my path of the performance script, but you have to change this to where you have saved the script

Have fun!
Jan

Last edited by Lontronics (2007-04-17 20:30:57)

drakosha · 2007-04-16 07:50:48

Did you try to put /tmp only on ramdisk? Did you feel any speed up? I believe that home directory on a ramdisk is dangerous - however /tmp is a great idea.

klixon · 2007-04-16 08:05:41

Is there any objection to putting the script in /etc/rc.d and calling it from the DAEMONS-array in rc.conf?
I'd say that would be a somewhat neater way of doing this than messing with rc.{sysint,shutdown}...
Otherwise... maybe just tmp for me... I'll just stick to a solid home
Nice work though...
I'd change

NAME=($(grep ^audio /etc/group | sed 's/audio::[0-9]\{2,3\}://g' | tr ":" " "))

into

NAME=($(grep ^audio /etc/group | cut -d: -f4))

On the off chance that someone might have provided a password or something else out of the ordinary to the audio-group though. It outputs field 4 of a ':'-delimited input

Last edited by klixon (2007-04-16 08:14:42)

Lontronics · 2007-04-16 19:33:16

@drakosha;

Yes I did, but not for getting better performance. The noticable difference is less writing to the disk, especially with the other settings used in the script. But why not trying yourself with a /tmp ramdrive ?

@klixon;

Thanks for the compliment.
And about your line of script; thanks too, although you were forgotten one thing to make an array from it.
Will use cut though, simple indeed
Line is now:

NAME=($(grep ^audio /etc/group | cut -d: -f4 | tr "," " "))

I think it is not wise to run it from rc.conf because I make a new /<ramdrive>/tmp before something is done with it.
But I will see if it is possible; indeed neater.

Jan

Last edited by Lontronics (2007-04-16 19:58:01)

Arch Linux

#1 2007-04-15 21:46:34

Performance script (dangerous)

#2 2007-04-16 07:50:48

Re: Performance script (dangerous)

#3 2007-04-16 08:05:41

Re: Performance script (dangerous)

#4 2007-04-16 19:33:16

Re: Performance script (dangerous)

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