Tony,
I totally agree with what John has just written, thought I might add:
I am sure that 10% of DVD-R or DVD+Rs may 'fail' in the first year,
but that does not mean that they do!
The biggest difference to failure rates is the quality of the
original media and the care that you take to create them. The top
manufacturers test their disks and sell on those that do not come
quite up to standard to less scrupulous re-sellers who sell them
unbranded. So stick to the big branded names and buy 'archive'
quality discs if they sell them. I used to recommend Kodak, but now
normally use Sony or Mitsui Archive discs.
Stick to known best practice when writing and using DVD-R & DVD+R
media. Won't go into this here, but check TASI site or other for
details. This really makes a difference.
If you stick to doing this, my experience is that failures are much
fewer and although I have not quantified this....well under 1% a
year. Those that do fail are normally due to obvious problems like
physical damage.
DVD-RAM is reputedly more reliable than DVD-R or DVD+R, but I have
seen no definitive evidence for this. In fact I don't think the
technology is close to that used in MO, but rather is much the same
as is used in DVD+RW and DVD-RW, which do not have a particularly
good reliability record, the difference is that DVD+RW and DVD-RW
collate date in one concentric line, whilst DVD-RAM has a sector
system and better fault control. The earlier DVD-RAM discs came in a
caddy, which certainly gave them some extra protection, but current
discs have lost this advantage. For me, the biggest problem for
using DVD-RAM ( or DVD+RW and DVD-RW) is that they are multi-write
and note Write Once Read Many drives. Personally for normal image
archive use, I much prefer the security of a WORM drive.
LaCie has in the past had a very good reputation, especially in
commercial imaging organisations. I am sure they are still
good....but technology has moved on a fair bit and the discs they use
are still just normal SAIT discs inside. So I think there are other
similar desktop RAIDs or other Network Assisted Storage answers which
could easily provide the required functionality. For instance Maxtor
have a 1 Terrabyte RAID based on their SAIT disks for an incredible
600GBP or so. Of course you can also do as John suggested and put a
couple of 500GB discs in an old PC and mirror those for very cheap
and easy extra backup storage.
There are various competitors to DiskWarrior, but none that I can
promise are quite as good! You might want to look at Disk Checker
at: http://www.rssoftlab.com/
I am not aware of any MAC or PC software that monitors file
corruption 'on-the-fly' in the background....the only ones I have
heard of, you have to initiate a scan and revue the results.
But the most important part of this, in the end, is not really the
technology you choose.....but establishing exactly what your
intentions are for the image archive and using good practice to back
up those intentions.
For instance:
Are the images to be held in a 'working archive' or in a 'data vault'
with no access?
Are they the only up to date and accurate copy of image data?
Are they the primary version of data or secondary version?
Best practice would suggest at least two versions of storage
media. It can make sense to have two versions each with different
use - 'working archive' and 'data-vault'.
Data Vault: I still think that at present DVD-R provides
the best media for a 'data vault' where images are left and added to,
but not retrieved....unless working copy is lost.
Working Archive: It may be.....that a 'working archive' can
sensibly be held on disk, it must be regularly incrementally backed
up to the DVD-R data vault. If not, then again DVD-R would be my
primary choice.
Hope this helps
please do feel free to get in touch if I can be of any further help
cheers
eib
At 04/04/2006 17:56, you wrote:
>Dear All,
>
>In addition to our existing server setup and it's associated
>backups, we would like a separate system to backup important RAW
>camera files and other critical files, but are unsure of a suitable
>strategy. Does anyone have any recommendations, such as desktop RAID
>hard drives, DVD backups, something else or just use every available
>media type!?!
>
>Knowing that 10% of CD/DVD's can fail every year doesn't seem to
>make this a great option, however apparently DVD-RAM is more
>reliable as it is closely related to MO disks. Any thoughts? Is
>there a good known brand of CD/DVD's?
>
>Does anyone have any experience of the Lacie RAID desktop hard
>drives or similar? If we used the drive connected to a Mac and had a
>copy of DiskWarrior would this give some confidence in the case of
>file corruption? Is there a PC equivalent of DiskWarrior?
>
>Finally is there any MAC or PC software that can monitor (image)
>file corruption or am I simply asking too much of modern technology!!
>
>Many Thanks
>
>Tony Harris
>New Media Officer
>Government Art Collection
>0044 (0)20 7580 9123
>
>www.gac.culture.gov.uk
>
>
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