Should I backup to optical disc and why?

Question

I am considering including duplicating to bluray once or twice a year into my backup strategy and would appreciate input on pros and cons.

Advantages I assume:

• immune to EMP/electric surge

Disadvantages I assume:

• slow
• limited space
• only write once

Am I correct in my assumptions? What other advantages and disadvantages do this medium have? What is the life expectancy of an optical disc? How far from an atomic blast will they survive?

Edit: I do not feel that my question is a duplicate of the suggested questions. Their answers do contain relevant information but the questions themselves have a different primary focus.

Solution

You are on the right track with your assumptions.

Advantages:

1) Immune to EMP/electric surge:

In general day to day use, yes, especially when compared to say a hard drive. As for the EMP part (hopefully we never find out), it would depend on several conditions, though it would most likely survive much better than a HDD

Disadvantages:

1) Slow:

Depends on your equipment, particularly the speed of the Blu-ray optical drive being used. Wikipedia has a nice summary of speeds: https://en.wikipedia.org/wiki/Blu-ray_Disc_recordable#Speed Hard drives and SSDs would most likely be faster.

2) Limited space:

Yes, Blu-rays have limited space per disk but so do any storage devices. Compared to modern consumer HDDs/SSDs the space per Blu-ray is relatively low, however, this is not really an issue as Blu-rays are generally significantly cheaper than a HDD/SSD of the same size.

3) Only write once:

If you use a single write Blu-ray, yes. Re-writable Blu-ray discs are also available.

This site is a good summary of the pros and cons of backing up to Blu-ray: http://www.databackuponlinestorage.com/Blu-ray_Optical_Discs

As stated per the link above, it is difficult to accurately state the life expectancy of a Blu-ray, although theoretically they could last 50-200 years. Practically, their lifespan is dependent on how long the Blu-ray standard is supported.

Like any optical disc, there are three primary dangers:

1. Direct sunlight
2. Excessive heat
3. Scratches

Scratches are easily avoided by storing them suitably, usually in a high quality 'disc wallet'. Heat is avoided by storing them in a relatively cool location, ideally no warmer than room temperature.

In terms of extreme surviving an atomic blast or something extreme, it's not very likely. Perhaps they would survive a flood for example, assuming they remain protected in a case. As for other disasters, chances are low.

Comments

[Breakthrough]

possible duplicate of Long-term backup storage media, What medium should be used for long term, high volume, data storage (archival)?, How to store and preserve lots of data?, or How much time until an unused hard drive loses its data?

[Joris Groosman]

Due to write-once you'll also have the advantage of being able to go back more than one version of your files. A drawback of write-once is that each backup will cost you money.

[CodeCaster]

superuser.com/questions/251369/…

[gaborous]

Note that Blu-Ray HTL discs tend to be quite almost invincible against sunlight damages (contrary to DVDs), and that using re-writable discs will probably lower the longevity a lot (just like for DVD-RW). About the danger of scratches, you can raise the probability of recovery by adding bitwise error correction using DVDisaster (Blu-Rays have higher error correction compared to DVD, but it's still low for long term archival).