Arch Linux

tomfitzyuk

Member

Registered: 2005-12-30

Posts: 89

Creating a backup of a hard drive continuously

Hey,

I'm thinking of getting another hard drive which would be for backing up my entire hard drive.

I'm not sure whether I'd want this to backup continuously (i.e. if I downloaded a file, it would go straight to both hard drives) or backup at certain intervals (i.e. at the end of every hour replicate the original drive, the advantage to this would be that if ever I accidentally deleted something I needed, say, ~, I would be able to copy it from my backup hard drive to my original hard drive).

So what's peoples thoughts on this?

How do *you* backup your data?

Thanks
Tom

dmartinsca

Member

Registered: 2006-04-13

Posts: 3

Re: Creating a backup of a hard drive continuously

If you are considering buying another drive to backup data you might want to look into setting up a software RAID 1. Software RAID allows you to mirror your data on two partitions on separate drives. When something is written it automattically goes to both drives, i guess this means if you delete something it is deleted from the other drive as well so it doesn't protect against user error! In theory this can boost performance when reading information from disk because there is two locations it can be read from.

I currently do 3 backups, one of my home folder, excluding my music, one of my music, and one of my root filesystem, excluding some directories. I have been using dar for this as it creates nice compressed archives, allows you to split them, and lets you retrive any file from within any piece of the archive. There is also a frontend called Kdar. I have been telling dar to split the archives into 2GB slices and saving them to DVD or storing them on my windows PC using samba. I use 2GB slices because the iso filesystem used when writing DVDs doesn't like single files larger than 2GB.

Someone just pointed me to an app called scdbackup: http://scdbackup.sourceforge.net/main_eng.html
It allows you to write directly to cd/dvd which is a nice feature. It doesn't look like it has been built for arch yet so i'm going to look into doing that (although i am brand new to this distro).

Snarkout

Member

Registered: 2005-11-13

Posts: 542

Re: Creating a backup of a hard drive continuously

I rsync my home directory to an external drive once a day.  If I lose anything from that day that I really need, I'm screwed I guess, but it's better backups than I've had ever before.  I also have a hardware based raid5 array, which sucks performance-wise (any high i/o and I might as well go make a sammich) but actually saved my ass when a 3 month old drive ate death.  FWIW, oftware raid eats up a lot of cpu.

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Unthinking respect for authority is the greatest enemy of truth.
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Gullible Jones

Member

Registered: 2004-12-29

Posts: 4,863

Re: Creating a backup of a hard drive continuously

Yup, IIRC there's a 30% CPU overhead.

(BTW, why is it that modern hard drives die after a few years while old ones keep chugging away for a decade? Is it a case of "Made In China" syndrome?)

kth5

Member

Registered: 2004-04-29

Posts: 657

Website

Re: Creating a backup of a hard drive continuously

Yup, IIRC there's a 30% CPU overhead.

(BTW, why is it that modern hard drives die after a few years while old ones keep chugging away for a decade? Is it a case of "Made In China" syndrome?)

yes but there's more to it than that i guess. who would buy a new harddrive at all nowadays? unless you store tons of music, video and other space intensive things 80gb are more than enough as long as they work... but what if...

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I recognize that while theory and practice are, in theory, the same, they are, in practice, different. -Mark Mitchell