[ale] Backup large files to span DVDs

[Alex Carver]

On 2015-10-28 11:46, James Sumners wrote:
> On Wed, Oct 28, 2015 at 2:37 PM, Alex Carver <agcarver+ale at acarver.net>
> wrote:
> 
>> I understand that it's not a file format itself but it does require an
>> additional utility to implement the method (the parchive client) and
>> that's what I'm not allowed to use.  Generating the parity files would
>> just be a waste of time in this case because I would not be able to get
>> the utility approved.  The current approved method for corruption
>> mitigation is multiple media types and duplicate copies (e.g. a magnetic
>> copy, an optical copy, a hard copy for things that can be printed, etc.)
>>
>> I'll certainly consider it for my personal data storage because it looks
>> like a good thing to have, but I just can't do it at work.  This is why
>> there are ten hard drives, many spindles of disc blanks, and lots of
>> binders at my desk.
>>
> 
> I am glad I do not work where you work. Redundancy doesn't imply corruption
> mitigation. And refusing to allow such to be implemented because the tool
> isn't "old" is asinine.

<shrug> I just do my work, I don't bother to get into the details of why
they choose to do what they do.  It's not that the tool isn't old, it
just isn't validated to their liking.  Parchive already has three
specifications/versions and versions 1 and 2 are incompatible with each
other.  On the other hand, tar and cat haven't really changed so they're
stable with respect to old copies of data.

Now, if parchive were validated then I could use it.  Plenty of other
"young" tools have been approved for various purposes, too.  But when
archival data has to exist and be readable after 50 to 100 years, your
selection of tools gets limited.  Part of that means that tools would
ideally need to already exist (rather than needing to be written from
scratch) in the future to read those data files from the past.  So
that's why tar is ok, it's already almost 30 years old and hasn't really
changed much so it's likely to exist 30 or more years from now.

If I pushed, I could probably get a waiver to use it since it doesn't do
anything to the stored data itself, just generates additional parity
data.  But until the specification calms down it's not likely to get
approved as a generally acceptable tool.