JiscMail Logo
Email discussion lists for the UK Education and Research communities

Help for MCG Archives


MCG Archives

MCG Archives


MCG@JISCMAIL.AC.UK


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

MCG Home

MCG Home

MCG  2006

MCG 2006

Options

Subscribe or Unsubscribe

Subscribe or Unsubscribe

Log In

Log In

Get Password

Get Password

Subject:

Re: Backup strategy/file corruption

From:

Ed Bremner <[log in to unmask]>

Reply-To:

Museums Computer Group <[log in to unmask]>

Date:

Wed, 5 Apr 2006 10:42:37 +0100

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (150 lines)

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
>
>
>______________________________________________________________________
>This email has been scanned by the MessageLabs Email Security System.
>For more information please visit http://www.messagelabs.com/email
>______________________________________________________________________
>
>**************************************************
>For mcg information and to manage your subscription to the list, 
>visit the website at http://www.museumscomputergroup.org.uk
>**************************************************

Ed I Bremner
BremWeb Imaging
[log in to unmask]
http://www.bremweb.co.uk
h: 01822 832574  m: 07973 335509  

**************************************************
For mcg information and to manage your subscription to the list, visit the website at http://www.museumscomputergroup.org.uk
**************************************************

Top of Message | Previous Page | Permalink

JiscMail Tools


RSS Feeds and Sharing


Advanced Options


Archives

May 2024
April 2024
March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
2006
2005
2004
2003
2002
2001
2000
1999
1998


JiscMail is a Jisc service.

View our service policies at https://www.jiscmail.ac.uk/policyandsecurity/ and Jisc's privacy policy at https://www.jisc.ac.uk/website/privacy-notice

For help and support help@jisc.ac.uk

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager