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Re: backup compress on the fly




On Mon, 3 Oct 2005, Mike McCarty wrote:

> The point is that, if there is an error, all the CRCs in the
> world won't put the data back together again. If one uses

crc or ecc ??

most "large capacity" drives uses ECC which does support error correction
at least in the firmware and tape controllers to read the data
off the tape ..

> OTOH, if the
> whole image on tape is a compressed one, then tar or gunzip or whatever
> is simply going to complain that the one (and only) file in
> the compressed archive is corrupt and unrecoverable.

there's an asumption that you only have 1 compressed file
on the tape

whilest you can in fact have multiple files on the tape

<flame bait>
tapes for backups is like to stoneage of the flintstone
</flame suit left on>
	- tapes are good for the lawyers and archives only

- but for security .. tapes should only be a
  backup of each of the raid5 disks SEPARATELY, 
  so that if some bozo gets their paws on the 
  backup system, they cannot read/find ANY useful data ..

	- i'd never store "data other people can read"
	off the tapes, as you donno who is reading the tape
	and since oyu don't check that the tape is still
	in the vault "today, right now" who knows where it is

c ya
alvin



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