Current thinking on bit rot/bit flip

[WebHead]

As an OCD type I'm periodically worried about the possibility of bit rot on my archived hard disks. Linus Torvalds' comments this week on ECC RAM reawakened my fears.

Over the years I've read numerous opinions on bit rot, whether it's real, a myth or just overblown, and the best ways to prevent (or at least delay) it.

So I was wondering a couple of things:

• Should I be concerned about bit rot, and if so
• Will periodic powering up and scanning of drives safeguard them, or does the data need to be rewritten to remagnetise them?

 

[BrianBaughn]

If you are shelving hard drives for archival purposes then you should be concerned. If you only have one copy of the data you are living on the edge.

I don't know if powering/scanning helps by itself.

It might help if you describe your current archiving situation.

Personally, I don't have anything archived "on a shelf". My disks are active and I clone a couple every night and a few other less active ones every few weeks using Carbon Copy Cloner.

If I did have a shelved drive as an archive I don't think I'd feel good about it unless I have one duplicate of it and, every month or so, put them on a two-bay docking station and use CCC to clone from one to the other. CCC checks the source for errors while cloning, so I'd probably rotate which drive I cloned to the other.

 

[retta283]

A good backup system is maintained consistently. Buy new drives, keep multiple copies, keep the drives at least somewhat active, have a master drive or two in addition to clusters of system backups if you are maintaining a collection of data.

 

[s66]

Synology (and probably other NAS too) has features where the NAS will perform active scans of all their disks to see if the RAID checksums are still OK across all their disks. It's a task you can schedule (I do mine every 6 months on a RAID 6 volume). It'll read everything and verify the checksums are still OK.


CCC: careful: it does not always copy everything, it can also just do an incremental copy and then it would not notice the disk going bad in sectors it does not overwrite on the destination or read on the source.

Archives need to be managed, you cannot put them on any medium and forget about them forever. You need to every so often copy it all onto a newer medium, even a newer technology as it evolves. Digital archives need that, and contrary to analog archives, if done right you do not lose information.

Also beware that the files themselves might need to be converted. E.g. really old word .doc files cannot be opened by a modern version of MSFT's word any longer. There are better and worse archival formats, but nothing can prevent a format to go so far out of fashion that nothing will open it any longer if you do not take care of it in time.

 

[WebHead]

Neglected to mention I have 2 x HD copies and am planning to back up the most critical data to Blu-ray as well. Thanks for the input folks!