On 12/07/13 12:05 PM, Ralf Mardorf wrote:
On Fri, 2013-07-12 at 11:34 -0400, Gary Dale wrote:
On 12/07/13 09:43 AM, Ralf Mardorf wrote:
On Fri, 2013-07-12 at 14:26 +0200, Helmut Wollmersdorfer wrote:
Am 12.07.2013 um 11:50 schrieb Ralf Mardorf:
OT: DVDs aren't safe medias for backups.
Hmm ... How safe is safe for backup?
At home I rsync to an external SATA disk with 1 TB.
And for musik, foto etc. I have 4 external USB-HDDs, each 0.5 - 1 TB.
Burning DVDs is too much work.
That burning split archives is a PITA is the other good reason not to
use DVDs ;D.
External HDDs are the better medias for backups at home. DVDRAM
theoretically would be ok too.
CDs, DVDs and USB sticks etc. aren't safe medias. I guess we all
experienced that data is less safe on those medias.
I don't know what is used for what kind of professional backup. Since
I'm a musician and I used DAT for mastering audio productions, I
wouldn't use that kind of tape to backup computer data. As fat as know
those tapes are often used for backups, they aren't called DAT, but the
machines and tapes are the same. Sometimes I used data tapes for audio
recordings.
I experienced floppy disk as very safe, I still own some as old as a
T-Rex, even high density disks that were used with averaged double
density drives are still ok.
DVDRAM was a great backup medium. Unfortunately it's hard to get these
days and the capacity is limited. BD-RE uses the same basic technology,
is easy to find and has much better capacity.
You also need to distinguish between backup and archive. Backup media is
reused multiple times. Archive media is written once but may be read
from time to time. Archive media needs to be stable for long periods.
This eliminates external HDDs.
Archiving to a RAID array makes sense, as does writing to BD-R disks.
The former is reasonably safe with good capacity but unfortunately
consumes power when running. Making multiple copies to BD-R gives you
some degree of safety.
BD writers are cheap enough these days that you shouldn't be talking
about backing up large amounts of data to DVD.
I was thinking of "archiving" as a kind of "most safe kind of
backup" ;).
An issue for archiving also is to get the device that is able to read
the media, that includes the data, that is safe on this media for the
next 1000 years ;). It's useless to have the data on a media, if you
don't have the machine to read the data.
SyQuest medias, FloppyDisks, DAT-tapes here still archive unbroken data,
just the readers tend to fail ;).
Did I already mention that I just for one time in my live made a big
mistake and randomly deleted the only available backup? The possibility
to do this was close to impossible, but close to impossible still is
possible :D.
I'd be happy if my data outlives me. :)
BD and other optical formats have been quite popular so the possibility
that they will be readable over the next decade is quite good. There
will still be optical drives in 10 years time that will be able to read
the disks and transfer the data to another format.
The ability to have multiple copies is important, as you (and everyone
else) have found out. Single copies go missing, fail or get destroyed.
That gives an edge to systems that have low media costs, like BD-R,
where it's easy to make multiple copies of important archives.
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