Looking for backup solution that uses multiple DVDs
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Looking for backup solution that uses multiple DVDs
As the subject says, I'm looking for a backup solution that works with my DVD writer.
I searched the forum and everything I found assumes you have a tape drive or a large disk on which to put everything. I have neither.
My only choice is to use my DVD writer. I have been using k3b, but, it's not ideal. For one thing, my home directory exceeds the capacity of a DVD. So much manual tweaking is required to make a backup. Second, there is no way that I've found to do incremental backups with this approach.
So, my requirements are for a backup method that can span a backup over multiple DVDs. It should allow both full and incremental backups. Naturally, search and restore capabilities are a must.
Edit:
One suggestion when using dar to write DVDs. Use 4 x 1.1GB slices for one DVD for maximum efficiency. You cannot write one large slice due to a size limit.
Edit:
One suggestion when using dar to write DVDs. Use 4 x 1.1GB slices for one DVD for maximum efficiency. You cannot write one large slice due to a size limit.
Thanks. This looks very promising. One thing that is not immediately obvious to me is if I need to manually format my blank DVD-R.
I'd just use tar, split, and growisofs in a script
Care to share that script?
Keep in mind that I do not have enough space to store a full backup of my system, which is why I need to split across DVD in the first place. Also, does your solution provide incremental backup?
One suggestion when using dar to write DVDs. Use 4 x 1.1GB slices for one DVD for maximum efficiency. You cannot write one large slice due to a size limit.
I use dar heavily but am not aware of that problem and workaround. Could you give some more detail?
Keep in mind that I do not have enough space to store a full backup of my system, which is why I need to split across DVD in the first place. Also, does your solution provide incremental backup?
An alternative would be to split your backup into parts, each of which fits on a DVD. This facilitates backing up fats-changing data frequently and slow-changing data less often. In this way I avoid having incrementals which a) are more difficult to restore from and b) may require all DVDs in each set to be readable.
DVDs are notoriously unreliable media. They were designed for video where a few errant bytes don't matter. DVD-RAM is one solution but it is exotic and hence expensive (and there's less choice of drives that support it). Another solution is error checking and correcting for which par2 is the most popular software.
If you are happy to drop the incremental requirement and to split your backups into chunks of maximun one DVD size, I have a mature (and documented!) shellscript utilty complete with installation utility including checksumming. It uses dar, verifies the on-disk dar backup file, writes to DVD with par2 files and verifies the files on DVD. The tar.gz file is available here.
It is not necessary to format DVDs before writing to them, in fact it is not recommended because it reduces the life of the DVD but I have found it useful at times when Linux has difficulty writing to the DVD.
If you do decide to use dar, it is a good idea to familiarise yourself with restoring from backups. Dar's restore facilities are very powrful and, like most very powerful software, takes some mastering.
Last edited by catkin; 09-11-2009 at 11:52 AM.
Reason: English as she is rotten!
An alternative would be to split your backup into parts, each of which fits on a DVD. This facilitates backing up fats-changing data frequently and slow-changing data less often. In this way I avoid having incrementals which a) are more difficult to restore from and b) may require all DVDs in each set to be readable.
DVDs are notoriously unreliable media. They were designed for video where a few errant bytes don't matter. DVD-RAM is one solution but it is exotic and hence expensive (and there's less choice of drives that support it). Another solution is error checking and correcting for which par2 is the most popular software.
If you are happy to drop the incremental requirement and to split your backups into chunks of maximun one DVD size, I have a mature (and documented!) shellscript utilty complete with installation utility including checksumming. It uses dar, verifies the on-disk dar backup file, writes to DVD with par2 files and verifies the files on DVD. The tar.gz file is available here.
It is not necessary to format DVDs before writing to them, in fact it is not recommended because it reduces the life of the DVD but I have found it useful at times when Linux has difficulty writing to the DVD.
If you do decide to use dar, it is a good idea to familiarise yourself with restoring from backups. Dar's restore facilities are very powrful and, like most very powerful software, takes some mastering.
You may also like to look at the links in the "Known Projects that use dar or libdar" section of dar's documentation.
It includes HUbackup (denotes Home User backup). When I was looking for a DVD-based backup solution 15 months ago, HUbackup was one of the most promising candidates but there were too many reports of people not being able to restore from backups (!). Maybe HUbackup has improved; maybe there was nothing wrong with the backups themselves but the interface to dar's (non-trivial) restore facilities was defective.
We have to use DVDs here because the temperature, humidity and consequent burgeoning micro-life means tapes are not an option. What's your reason?
We have to use DVDs here because the temperature, humidity and consequent burgeoning micro-life means tapes are not an option. What's your reason?
It's what I have available. The computer is a laptop. Linux is not "supported" where I work, so backups are my business. The department that bought the laptop would not, at this point, buy a tape drive (I had to convince them to replace my dead battery). The location where I work (a different department) will not touch another's IT. I can't afford (I don't think) to buy one out of my own pocket.
Glad you asked?
That said, I really should look into something to back up home stuff too.
Keep in mind that I do not have enough space to store a full backup of my system, which is why I need to split across DVD in the first place. Also, does your solution provide incremental backup?
Well I guess that's not an option for you since space is an issue. You could compress, but that probably wouldn't save an incredible amount of space and there would be more of a chance of data loss. I was talking about something like this:
-------------
tar cvO $HOME | split -b 4G - xyz
for piece in xyz*
do
eject /dev/hdd
echo "Insert blank disc and press enter"
read
growisofs -Z /dev/hdd $piece
done
--------------
But of course this requires a lot of free disk space. Like I said you can also pass the z or j flag to tar to save some but I don't know how much it would be and then it'd be less reliable.
One thing I can recommend with a home-grown script is using the p7zip utility. It takes a long time to decompress from max compression, but I've gotten 1GB binary files down to 400M with it.
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