backups to cd and other disks and maintaining file attribs
Any recommendations on how to maintain the attribs (user/group/perms/dates...) of files when they are burned to a cd/cdrw/dvdram, or copied to another partition, and later need to be restored to their original form? comments on how to handle links? thanks
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 hanasaki wrote: | Any recommendations on how to maintain the attribs | (user/group/perms/dates...) of files when they are burned to a | cd/cdrw/dvdram, or copied to another partition, and later need to be | restored to their original form? | | comments on how to handle links? | | thanks Rock Ridge keeps track of permissions on iso9660 Chris - -- I digitally sign my emails. If you see an attachment with .asc, then that means your email client doesn't support PGP digital signatures. http://www.gnupg.org/(en)/documentation/faqs.html#q1.1 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFBMfSsE5xXU3JS1mQRAvdHAJ0VjIASUV8M5bxSYaLbuMd7g01YvgCgiXh2 FNLX3qyT3GSDJWP2L9Os/9M= =GK79 -----END PGP SIGNATURE-----
hanasaki wrote:
Any recommendations on how to maintain the attribs (user/group/perms/dates...) of files when they are burned to a cd/cdrw/dvdram, or copied to another partition, and later need to be restored to their original form?
comments on how to handle links?
Tar's default behavior handles archiving permissions and symlinks in their exact state as it should, by default. I recommend looking at the help text for --derefference and --check-links on the third page of 'info tar'. Use "/" to activate the search function in the info browser.
hanasaki wrote:
Subject: backups to cd and other disks and maintaining file attribs
Oh yes. I should also mention that RW-media of all types is little more than a film that changes its color under the write laser. Like film, there are a number of environmental conditions that can contribute the the media failing. I've heard as little as 3 - 5 years of shelf life is all you'll get out of the media. On the other hand, MO and DVD-RAM are attractive options. MO media has a rare-mineral substrate in which the electron spin of the mollecules can only be altered if the media has first been heated by the write laser to an astronomical temperature. Essentially, the data is store magnetically and its guaranteed to not do any bitflipping because the conditions to allow that to occur would never occur naturally. I'm not sure what MO is rated for in terms of shelf life but it is high. A protective cartridge is also mandated. DVD-RAM also has a substrate that's composed of some rare minerals -- the latest forms of DVD-RAM (5x) use bismuth coupled substrates. The write laser heats the localized area to 1,400F to change the reflective index to record a 1 bit. (4|9)00F is used to set it back to 0. These are changes that are much more substantive and thus, the shelf life here is approximately 30 years. Protective cartridge is optional.
On Sunday 29 August 2004 11:47 am, Jason Clinton wrote: Which is perplexing, because I don't know if it's an update to KMail that has rendered his posts as seperate text attachments again. Anyway, he cited DVD-RAM, Magneto-Optical devices and compared them to the CD/DVD RW discs for their superior durability. What do these devices cost these days, Jason? How about the media for them? Used 30G DLT Tape drives are about 150 on PriceWatch, new ones start at about $700, and the cartridges list at about $40/30G. I saw what looked like an 8G DVD recorder at CompUSA the other day - that would be a reasonable size to back up a lot of systems. Anybody know if there is 8G DVD media, or what it costs?
Jonathan Hutchins wrote:
On Sunday 29 August 2004 11:47 am, Jason Clinton wrote:
Which is perplexing, because I don't know if it's an update to KMail that has rendered his posts as seperate text attachments again.
It's due to the mailing list software appending that extra plain text to the end of an PGP/MIME message. I picked up a LG SuperMulti (supports burning all CD and DVD formats) for 95$. Media is $1 - $10/ea depending on parameters.
"hanasaki" <hanasaki@hanaden.com> wrote:
Any recommendations on how to maintain the attribs (user/group/perms/dates...) of files when they are burned to a cd/cdrw/dvdram, or copied to another partition, and later need to be restored to their original form?
You can use tar, which preserves all of that...
comments on how to handle links?
..and stores symlinks as symlinks, although it doesn't do so well with hard-linked files. (This is one reason that I generally prefer symlinks.) Or, if there's room, just DD the entire filesystem over to DVD.
participants (5)
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Chris Bier -
hanasaki -
Jason Clinton -
Jonathan Hutchins -
Monty J. Harder