Following this post what was left was to create a “automatic” method to remove old backups. Basically, I wanted the newsyslog(8) (or logrotate for the linux enthusiasts) functionality to my own custom solution. The previous way was semi-automatic since different requirements needed some manual intervation to prevent from deleting something by mistake.

Following the quick and dirty method to achieve it. I created a really simple script that was taking a “configuration” file that includes the backup directories and after visiting them deletes files that are older from a defined time frame. The script is the following:


while read dir time wctype
	if [ $wctype -eq 1 ]
	      num=`ls -l $dir | sed '1d' | grep -v ^d  | wc -l`
	      if [ $num -ge $time ]
		find "$dir" -mtime +$time -type f -maxdepth 1 -exec rm {} \;
#		find "$dir" -mtime +$time -type f -maxdepth 1 
	elif [ $wctype -eq 2 ]
	      files=`ls $dir | cut -d . -f 1 | sort -u`
	      for i in $files
		      num=`ls -l $dir/$i* |  sed '1d' | grep -v ^d  | wc -l`
		      if [ $num -ge $time ]
			      find $dir -name "$i*" -mtime +$time -type f -maxdepth 1 -exec rm {} \;
#			      find $dir -name "$i*" -mtime +$time -type f -maxdepth 1 
done < "$PATHTO/rotate.conf"

And the configuration file is simply

/backup/machine1			10	2
/backup/machine2			10	1

Some comments:

  • In the configuration file the first colum is the directory that the backup files exist, the second column (the number) is the number of days that you want to keep backups and the last column is either 1 or 2 and defines the backup type:
    1. type 1 is if you want to deal with all the files in the directory
    2. type 2 is when the files in the directory have a “structure” and you want to keep from all of them. For example in our case we backup mysql databases and we have the backup file named like

      . So with type 2 tries to check for each individual file and remove accordingly

  • The script tries to keep a number of backup files in place, if no update happens for a certain time. There have been cases that the backup stopped unexpectedly for quite some time, and by just removing files that are older will eventually destroy all the backups. The number of backups kept in this versions is the number of days that the user requests to keep. The way it is implemented has a number of shortcoming, for example what happens if we have 2 backups per day? Or 1 backup per week? However it is known issue and in the case it is used doesn’t matter much. Furthermore, lets suppose the backup process stopped for example 10 days, and we have kept the 9 previous files. The next day the backup succeeds, so the script runs and removes the previous 9 files, and we are just left with 1. In our case this is not much of an issue, since everything that is older than the number of days and we didn’t explicitly request to keep, can be removed

It is not a perfect solution, but at least keeps the drive from filling up.


Dial on demand on BSD

October 27, 2006

This is an old post .. from my first blog about Dial On Demand (DoD) on BSD systems. I think it might be useful for some people so I’m reposting it. Bare in mind that this post is a bit old , and some things my not be so accurate, but the logic behind it is still valid.

For a lot of reasons, I had to reboot my old pc at home to use it. (Actually even the newer stuff that i have at home are quite old, except my SUN blade 150) This PC has not been rebooted for almost 2 years, so when i booted it I found some of the stuff that i was doing back then. One of the things I did was to setup Dial On Demand. I usually have my desktop on so i just ping someplace, or use the browser and it automatically dials, get the data, and after some time just hand up (if i don’t use the net).

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