[ltp] Upgrading inbuilt DVD/CD drive

Sat, 29 Jul 2006 02:52:21 +0100

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Andrew Barr wrote:
> On Sat, 2006-07-29 at 02:05 +0100, Richard Neill wrote:
> 
>>I *think* you can use a stock model. However, why not buy a USB drive? 
>>It's probably cheaper. 
> 
> 
> Actually, the pricing I saw on USB drives versus the slimline drives was
> about the same, in the range of $60-$70.

Perhaps more versatile though :-)

> 
>>You can also buy USB-IDE adapters for about $40, 
>>which will work with any IDE drive; this would also allow you to have an 
>>external Hard drive.  (check Linux support first though, just in case).
> 
> 
> I don't need any more disk space (100GB), and I am already looking at a
> 2.5" USB drive enclosure for my old hard disk to use with my Nokia 770.
> 
> 
>>Lastly, it is possible that this is a case of "to get there, you don't 
>>start from here". Unless you actually want to burn video-DVDs to play in 
>>a standalone player, there might be a different way to solve your 
>>problem. What do you want the DVDs for?
> 
> 
> Backup, mostly. I have a large collection of music, TV shows, and a few
> movies that I don't want to lose in a hard disk crash. I've also been
> playing around with some different Linux distributions and some are on
> DVD. I use QEMU when I can but sometimes I want to run them on real
> hardware.
> 

I thought you might say that. I think you might be better off with an 
external HDD than burning to DVD. 3 advantages:

- Copying to HDD is much faster (especially if you use rsync) - the 
script I use is attached (no need for the HDD to be a firewire one 
rather than USB)

- Easy to do lots of incremental (yet full) backups. [This is very 
clever - see the shell script for more details - although the idea is 
not mine!]

- HDDs are as reliable as DVDs. I.e. neither is fabulous, but optical 
disks only last 5 years.

You might also consider network-based backups. Rsync + SSH = Happiness!

However, of course it's your decision! Good luck with whatever you 
decide on. HTH.

Richard

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#!/bin/bash

#This does a backup from the host computer to a locally connected firewire HDD using rsync and ssh. It then rotates the backups. Run it via cron every night at 5am.
#This only backs up the home directory. If ownerships (other than the user's) should be preserved, then run the rsync process as root (and re-instate the -o).
#We save every day for 7 days, then every week for 4 weeks, then every month for 3 months.
#See: http://www.mikerubel.org/computers/rsync_snapshots/  for more explanation of the theory.
#Save as: $HOME/bin/nightly-backup_firewire-hdd.sh

##### BEGIN CONFIGURATION SECTION ###############################################################
LOCAL_USER=rjn				#User whose home directory should be backed up.
MOUNT_POINT=/backup			#Mountpoint of backup drive. NO trailing slash! This must be unique (eg using a udev symlink)
SOURCE_DIR=/home/$LOCAL_USER		#NO trailing slash - it DOES matter to rsync.
BACKUP_DEST_DIR=$MOUNT_POINT/backup/`hostname -s`.${LOCAL_USER}.nightly_backup
DRY_RUN=false				#If true, invoke rsync with -n, to do a dry run. Comment out or set to false for normal use.
VERBOSE=false				#If true, make rsync verbose. Comment out or set to false otherwise.
COMPRESS=false				#If true, compress. Good for internet, bad on LAN. Comment out or set to false otherwise.
##### END CONFIGURATION SECTION #################################################################

#Check that all the important variables have been set:
if [ -z "$LOCAL_USER" ] || [ -z "$SOURCE_DIR" ] || [ -z "$MOUNT_POINT" ]  || [ -z "$BACKUP_DEST_DIR" ];then
	echo 'One of the variables is not set! Edit the file: $0. BACKUP FAILED.'
	exit 1
fi

if [ "$#" != 0 ] ;then
	cat <<-ENDOFTEXT
	Automatic Nightly backup run from cron. Read the source for more details: $0
	The backup directory is $BACKUP_DEST_DIR . It will be created if necessary; initialisation is no longer required.
	WARNING: Contents of $BACKUP_DEST_DIR are rotated. Directories named 'backup.\$i' will eventually be DELETED.
	We keep backups from every day for 7 days (1-8), then every week for 4 weeks (9-12), then every month for 3 months (13-15).
	You may wish to add this to your crontab using 'crontab -e'
	    #Back up files: $SOURCE_DIR to $BACKUP_DEST_DIR every night at 3:15 am
	    15 03 * * * /home/$LOCAL_USER/bin/nightly-backup_firewire-hdd.sh
	Don't forget to verify the backups are working, especially if you don't read cron's mail!"
	ENDOFTEXT
	exit 1
fi

#Parse the options.
if [ "$DRY_RUN" == "true" ]; then
	DRY_RUN="-n"
	echo "WARNING: THIS IS A 'DRY RUN' - no data will actually be transferred!"
else
	DRY_RUN=""
fi
if [ "$VERBOSE" == "true" ]; then
	VERBOSE="-v"
else
	VERBOSE=""
fi
if [ "$COMPRESS" == "true" ]; then
	COMPRESS="-z"
else
	COMPRESS=""
fi

#Every week (actually of 8 days) and every month, extra backups are preserved.
DAY_OF_MONTH=`date +%d`    #Day of month (01..31).
if [ $DAY_OF_MONTH = 01 ]; then   						#First of month
	MONTHSTART=true
elif [ $DAY_OF_MONTH = 08 -o $DAY_OF_MONTH = 16 -o $DAY_OF_MONTH = 24 ]; then  #Day 8,16,24  (use 8, not 7 to better handle 31-day months)
	WEEKSTART=true
fi

#Check that the HDD is mounted. At least, check that *something* is mounted here!
#We can use something unique to the device, rather than just guessing the scsi-id by having an appropriate udev rule in /etc/udev/rules.d/10-rules.local
#and by putting a relevant entry in /etc/fstab. Eg: this udev rule:
#BUS="scsi", KERNEL="sd*", SYSFS{vendor}="WDC WD16", SYSFS{model}="00JB-00GVA0     ", NAME="%k", SYMLINK="lacie_1394d%n"

if mount | grep $MOUNT_POINT >/dev/null; then
	echo "Mount point $MOUNT_POINT is indeed mounted. OK"
else
	echo -n "Attempting to mount $MOUNT_POINT..."		#If it isn't mounted, try to mount it.
	sudo mount $MOUNT_POINT 2>/dev/null
	if mount | grep $MOUNT_POINT >/dev/null; then
		UNMOUNT_LATER=TRUE
		echo "OK"					#Note: Ensure that this is also unmounted if we exit prematurely with failure
	else
		echo "FAILED"
		echo -e "Nothing is mounted at $MOUNT_POINT. BACKUP FAILED"
		exit 1
	fi
fi

#Check source dir exists and is readable.
if [ ! -r  $SOURCE_DIR ] ;then
	echo "$SOURCE_DIR does not exist, or cannot be read. BACKUP FAILED."
	exit 1
fi

#Check that the backup directory structure is as it should be. If not, create it.
#Create the subdirectories. Note that backup.0 will be created as needed by rsync.
for ((i=1;i<=15;i++)); do
	if [ ! -d $BACKUP_DEST_DIR/backup.$i ];then
		if /bin/mkdir -p $BACKUP_DEST_DIR/backup.$i ;then
			echo "Warning: directory $BACKUP_DEST_DIR/backup.$i is missing, or was not initialised. (Re-)creating it."
		else
			echo "ERROR: directory $BACKUP_DEST_DIR/backup.$i is missing and could not be created."
			if  [ "$UNMOUNT_LATER" == "TRUE" ];then		#Before we exit, unmount the mount point if necessary.
				cd; sudo umount $MOUNT_POINT &&  echo "Unmounted $MOUNT_POINT again. Giving up."
			fi
			exit 1
		fi
	fi
done

#Set the permission to 700 for security on an otherwise permissive multi-user system.
if ! /bin/chmod 700 $BACKUP_DEST_DIR ;then
	echo "ERROR: Could not set permissions on $BACKUP_DEST_DIR to 700."
	if  [ "$UNMOUNT_LATER" == "TRUE" ];then		#Before we exit, unmount the mount point if necessary.
		cd ; sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again. Giving up."
	fi
	exit 1
fi

#Create the symlink: current -> backup.1 if required. A failure here is not critical.
cd $BACKUP_DEST_DIR
if [ ! -h current ] ;then
	if ! /bin/ln -s backup.1 current ;then
		echo "WARNING: could not create symlink current -> backup.1"
	fi
fi

#Now do the rsync.
echo "Now doing backup with rsync..."
echo "Source dir: $SOURCE_DIR"
echo -e "Backup destination dir: $BACKUP_DEST_DIR\n"

/usr/bin/rsync $DRY_RUN $VERBOSE -a -S --delete --modify-window=60 --link-dest=../backup.1 $SOURCE_DIR $BACKUP_DEST_DIR/backup.0/

#Only warn, rather than exit if the rsync failed, since it may only be a minor problem.
#Eg if one file is not readable, rsync will fail. - this shouldn't prevent the rotation.
#Not using eg `date +%a`  since these directories are just full of links and don't consume *that much* space.
if [ $? != 0 ];then
	BACKUP_JUSTINCASE=backup.`date +%F_%T`.justincase
	echo "WARNING: the rsync process did not entirely succeed. Something might be wrong. Saving an extra copy at: $BACKUP_JUSTINCASE"
	echo "WARNING: if this occurs regularly, a LOT of space will be consumed, even though these are just hard-links!"
fi

#Save a readme in the backup parent directory. Save another one in the recent subdirectory.
echo "Backup of $SOURCE_DIR on `hostname` was last run on `date`" > $BACKUP_DEST_DIR/README.txt
echo "This backup of $SOURCE_DIR on `hostname` was created on `date`" > $BACKUP_DEST_DIR/backup.0/README.txt

#If we are not in a dry run, rotate the backups.
[ -z "$DRY_RUN" ] &&

	#Check how full the backup disk is. Warn if 90%. if 98% or more, we'll probably fail, so give up. (Note: df can output to more than one line.)
	#We test this here, rather than before so that rsync may possibly have a chance.
	DISK_FULL_PERCENT=`/bin/df $BACKUP_DEST_DIR | tr "\n" ' ' | awk '{print $12}' | grep -oE [0-9]+ `
	echo Disk space check on backup partition $MOUNT_POINT $DISK_FULL_PERCENT% full.
      	if [ $DISK_FULL_PERCENT -gt 90 ];then
		echo "Warning: Disk is greater than 90% full."
	fi
      	if [ $DISK_FULL_PERCENT -gt 98 ];then
		echo "Error: Disk is full! Giving up."
		if  [ "$UNMOUNT_LATER" == "TRUE" ];then		#Before we exit, unmount the mount point if necessary.
			cd; sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again. Giving up."
		fi
		exit 1
	fi

 	#Create an extra backup. If this copy fails, give up.
	if [ -n "$BACKUP_JUSTINCASE" ];then
		if ! /bin/cp -al $BACKUP_DEST_DIR/backup.0 $BACKUP_DEST_DIR/$BACKUP_JUSTINCASE; then
 			echo "ERROR: Failed to create extra copy $BACKUP_DEST_DIR/$BACKUP_JUSTINCASE"
			if  [ "$UNMOUNT_LATER" == "TRUE" ];then		#Before we exit, unmount the mount point if necessary.
				cd ;sudo umount $MOUNT_POINT &&	echo "Unmounted $MOUNT_POINT again. Giving up."
			fi
 			exit 1
 		fi
	fi

	#At start of month, rotate the oldest 8
	if [ "$MONTHSTART" == "true" ] ;then
		echo -e "\nStart of month. Removing oldest backup: $BACKUP_DEST_DIR/backup.15"  &&
		/bin/rm -rf  $BACKUP_DEST_DIR/backup.15  &&

		echo "Rotating monthly,weekly backups: $BACKUP_DEST_DIR/backup.[8-14] -> $BACKUP_DEST_DIR/backup.[9-15]"  &&
		/bin/mv $BACKUP_DEST_DIR/backup.14 $BACKUP_DEST_DIR/backup.15  &&
		/bin/mv $BACKUP_DEST_DIR/backup.13 $BACKUP_DEST_DIR/backup.14  &&
		/bin/mv $BACKUP_DEST_DIR/backup.12 $BACKUP_DEST_DIR/backup.13  &&
		/bin/mv $BACKUP_DEST_DIR/backup.11 $BACKUP_DEST_DIR/backup.12  &&
		/bin/mv $BACKUP_DEST_DIR/backup.10 $BACKUP_DEST_DIR/backup.11  &&
		/bin/mv $BACKUP_DEST_DIR/backup.9 $BACKUP_DEST_DIR/backup.10  &&
		/bin/mv $BACKUP_DEST_DIR/backup.8 $BACKUP_DEST_DIR/backup.9

	#At start of week, rotate the second-oldest 4.
	elif [ "$WEEKSTART" == "true" ] ;then

		echo -e "\nStart of week. Removing oldest weekly backup: $BACKUP_DEST_DIR/backup.12"  &&
		/bin/rm -rf  $BACKUP_DEST_DIR/backup.12  &&

		echo "Rotating weekly backups: $BACKUP_DEST_DIR/backup.[8-11] -> $BACKUP_DEST_DIR/backup.[9-12]"  &&
		/bin/mv $BACKUP_DEST_DIR/backup.11 $BACKUP_DEST_DIR/backup.12  &&
		/bin/mv $BACKUP_DEST_DIR/backup.10 $BACKUP_DEST_DIR/backup.11  &&
		/bin/mv $BACKUP_DEST_DIR/backup.9 $BACKUP_DEST_DIR/backup.10  &&
		/bin/mv $BACKUP_DEST_DIR/backup.8 $BACKUP_DEST_DIR/backup.9

	else
		echo -e "\nRemoving oldest daily backup: $BACKUP_DEST_DIR/backup.8"  &&
		/bin/rm -rf  $BACKUP_DEST_DIR/backup.8

	fi  &&

	#Every day, rotate the newest 8
	echo "Rotating daily backups: $BACKUP_DEST_DIR/backup.[1-7] -> $BACKUP_DEST_DIR/backup.[2-8]"  &&
	/bin/mv $BACKUP_DEST_DIR/backup.7 $BACKUP_DEST_DIR/backup.8  &&
	/bin/mv $BACKUP_DEST_DIR/backup.6 $BACKUP_DEST_DIR/backup.7  &&
	/bin/mv $BACKUP_DEST_DIR/backup.5 $BACKUP_DEST_DIR/backup.6  &&
	/bin/mv $BACKUP_DEST_DIR/backup.4 $BACKUP_DEST_DIR/backup.5  &&
	/bin/mv $BACKUP_DEST_DIR/backup.3 $BACKUP_DEST_DIR/backup.4  &&
	/bin/mv $BACKUP_DEST_DIR/backup.2 $BACKUP_DEST_DIR/backup.3  &&
	/bin/mv $BACKUP_DEST_DIR/backup.1 $BACKUP_DEST_DIR/backup.2  &&
	/bin/mv $BACKUP_DEST_DIR/backup.0 $BACKUP_DEST_DIR/backup.1  &&

	SUCCESS=true

if  [ "$UNMOUNT_LATER" == "TRUE" ];then		#Unmount the mount point if it wasn't mounted to begin with
	cd ; sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again."
fi

if [ "$SUCCESS" == "true" ]; then
	echo 'SUCCESS!'
	exit 0
fi

echo 'BACKUP FAILED! Is this just a dry run? Is the disk full?) '
exit 1

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