[TriLUG] best dvd-r media

[Steve Litt]

On Monday 15 March 2010 15:40:41 Cristóbal Palmer wrote:
> On Mon, Mar 15, 2010 at 2:14 PM, Ralph Blach <chipperb at nc.rr.com> wrote:
> > Can anybody give any recommendations on the best DVD-r disk?  I need
> > these for Archiving.
> 
> Short answer: consider DVD+R over DVD-R and make multiple copies
> rather than trust the media. Longer answers:
> 
> http://www.thexlab.com/faqs/opticalmedialongevity.html#Anchor-Is-23240
> 
> and
> 
> http://adterrasperaspera.com/blog/2006/10/30/how-to-choose-cddvd-archival-m
> edia
> 
> Cheers,
> 

I've been using CD-R and DVD+R for backup since 1999, and as far as I know 
none of them have gone bad (I spot check every once in a while).

Like Cristobal I see monthly DVD+R backups as providing the redundancy to 
hopefully make things available even if a single backup set goes bad. I also 
keep the DVDs out of sunlight and in an air conditioned facility.

I see the greatest danger to long term archival to be software and hardware 
obsolescence. Has anyone tried to restore Fastback-recorded floppies lately? 
How about 5 1/4 floppies. QIC tapes? Now of course floppies and tapes are 
notoriously defective in their hardware, but even if they were perfect, the 
hardware and software to decode them isn't available these days.

What I do with archival backup is the following:

1) Use a long term standard common compression program to turn an entire tree 
into a single file. Before 2001 I used pkZip for this. After 2001 I used tar 
and gzip. The benefits here are:
	a) No restrictive ISO9660 or other standards to restrict filenames or path 
lengths
	b) Get much more backup data on a piece of media
	c) Include an md5sum so that years from now the whole file can be verified 
good by running md5sum and comparing with the original md5sum

2) Once I have the .zip or .tgz files, I look for very common hardware and 
software and media. I currently use mkisofs and cdrecord. These have been so 
common for so long that they'll be easily readable for years to come.

Actually I lied. I currently use a 2.5" hard disk in an enclosure. My .tgz 
files grew to the point where they surpassed 2.1G and needed UDF, which I 
understand may have some issues, so I started backing up to USB external hard 
drives. I hope later huge DVD type things become affordable so I can switch 
away from a media with moveable heads to one that can be stored in an 
envelope.

Anyway, my point is this: For true archiving, every 10 years you need to 
transfer the files to a more current, yet widespread and accepted media and 
software. Fortunately, every ten years, media size is a lot bigger so that's 
actually practical.

SteveT

Steve Litt
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