[clug] Neat Backup Solutions for desktops...

[steve jenkin]

Sam Couter wrote on 8/12/09 6:28 PM:
> Daniel Pittman <daniel at rimspace.net> wrote:
>> "Alastair D'Silva" <alastair at newmillennium.net.au> writes:
>>
>>> One problem with streaming encryption is that if you have any data
>>> corruption, data from that point on is lost.
>> Most of the encrypting done via a pipe is "streaming" only by choice, because
>> you selected an inappropriate feedback mode.  You could use a mode like ECB
>> that trades off some types of security in return for per-block protection.
> 
> What he said.
> 
> Also, compression usually has the same risk, where the compressed stream
> is invalid after the corrupted byte.
> 
> In Amanda's case, each filesystem is compressed and encrypted
> separately, so other filesystems on the same media won't be corrupted by
> one stray cosmic ray.

In my professional life, I can't remember once when I was able to
recover from backups easily/simply - sometimes, or at all.
This includes using commercial products & server-grade drives/media.

In 2003 I collected "war stories" about backups from a Sys Admin list.

In spite of extreme efforts, after 3-5 years media were found unrecoverable:

- 'A' wrote 3 optical disks on separate m/c, swap drives & verify (md5).
  Common faulty media blamed. Bad batch or dodgy manufacturer?

- 'B' wrote two copies, one to optical disk, another copy to DLT.
(verified?)
  Both media unreadable.

----

I'll second Sam, "what they said".
Easy to write data, harder to get it back.

-- 
Steve Jenkin, Info Tech, Systems and Design Specialist.
0412 786 915 (+61 412 786 915)
PO Box 48, Kippax ACT 2615, AUSTRALIA

sjenkin at canb.auug.org.au http://members.tip.net.au/~sjenkin