On Thu, 31 Jul 2008 21:04:06 +0100, Orchid XP v8 wrote:

> Jim Henderson wrote:
> 
>> It sounds to me like they lack an understanding of "archival" vs.
>> "backup".
> 
> Precisely.
> 
> (There's also talk about how to "back up" our software so we don't lose
> it.)
> 
> Note also that there is a regulatory distinction between the two terms,
> and the government holds us to those regulations.

Then in your comments, you need to cite the regulations in particular, 
along with the "definitions" section (if it exists; most regulations do 
have some section somewhere that defines terms).

>> ISTR this is typically done this so you could do restores of individual
>> files; if you needed to restore the entire system, you'd have to pull
>> the last full backup from offsite storage.  It depends on the value of
>> the data if its lost.
> 
> Actually it seems to be so they don't have to bother actually attending
> to the machine except once a week. To my mind, leaving all the tapes
> right next to the server rather negates the entire purpose of daily
> backups. If we're going to play that game, why not just only back up
> once a week?

Well, actually, it doesn't negate the purpose of daily backups.  You're 
assuming (perhaps) that the backups are useful only in case something 
catastrophic happens to he building - like it burns to the ground (in 
which case, your argument is valid).  But "dumb user Joe Smith" deletes a 
file he needs or it gets corrupted - having the backup right there is the 
fastest path to recovery short of an undelete utility (which can have 
their own problems).

> [Yeah, I realise it's not *quite* the same, but you see what I'm
> saying.]

Yeah, but that scenario is a single use case out of a few.  When 
structuring your arguments, you don't want to pick a specialized low-risk/
high-cost scenario and use that as the basis for your argument.

>> Agreed.  That said, doing a restore is much better than depending on
>> the tape drive's report during the backup of problems.  I've been
>> burned by that - it said data was being written, but it was unreadable
>> due to tape errors.
> 
> Standard procedure is to record the data, rewind the tape, read back all
> the data and check it actually matches what's on disk, not just that the
> checksums on the tape are OK. Still, it seems reasonable to go a step
> further and actually test the thing "for real" by actually performing a
> backup. I'm not sure it needs to happen every 3 months though...

That is a reasonable procedure IME.  A full restore on a regular basis 
isn't a bad idea, just to rule out the tape drive lying on its read 
test.  Incidentally, that's what I believe happened to me just before a 
catastrophic disk failure on a finance server that was followed by the 
realisation that we could not restore ANY of the data from the tapes 
because the tapes were part of a bad batch - and the software we used was 
too stupid to skip over read errors on a restore, but instead would abort 
the restore completely.

Even still, we did manage to recover 3/4 of the data with some help from 
the software vendor.

>> Just Invis' description sounds like GFS style backups.  It's a style
>> that some people find difficult to describe.
> 
> Yeah, it's GFS. However, the chart they supplied seems to indicate that
> there is only one grandfather tape, only one father tape, and only one
> son tape. In other words, if you want to restore from 2 days ago, the
> tape has already been overwritten. Like, WTF? So clearly that can't be
> what they mean. Hey, it's not like anything is *labelled* or anything
> like that...

Well, it depends partly whether incrementals are used for the F & S or 
differentials are used.  If a differential tape is done (ie, since the 
last F or G, depending on whether we're talking about the S or F tape), 
then it picks up all changes since the last "full" backup (ie, G or F 
tape).  I would probably prefer to use at least 2 tapes in the rotation, 
though when using differentials - if the write to the tape bombs the 
second time around, then you've also overwritten your earlier 
differential and you lose that much more data.  With two, you at least 
can go back to the previous day.

> As I asserted, it probably made perfect sense to the guy who scribbled
> it down.

Very likely.  One thing I do in situations like that is try to restate 
what has been stated and ask if my understanding is correct.  That 
usually helps the writer - especially if what you repeat back isn't what 
was meant.

Jim

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Orchid XP v8 wrote:
> They want to keep every monthly backup forever. The other tapes get 
> rotated for a year, and then the whole lot get "archived". So we have 
> full backups from each month, and then a load of differential backups 
> from the last few days of the year. Like, WTF?

So ask them when they'd expect to use those tapes. Maybe there's some 
regulatory or accounting mechanism that requires them to be saved. Point 
out where files that were changed in October won't be saved on either 
the Jan or Dec tapes. Ask them under what situations they'd expect to 
use the differential tapes.

>>> I suggested MD5 hashes or something would be a good idea. I even 
>>> suggested a procedure for using 'em...
>>
>> What's wrong with "comp"?
> 
> Does that exist on Windoze?

It exists in DOS 1.0 and everything after it.

> particular scenario, a basic file compare would be fine. (We would 
> probably have to formally test the correctness of the compare program 
> though!)

You could probably do that if you wrote it in Haskell. ;-)

> The chart *is* a calendar - but it shows only 1 son tape, 1 father tape, 
> and 1 grandfather tape, which makes no sense at all. But then, none of 
> the parts are labelled, so you have to take guesses at what it's saying...

Ask to clarify. Or guess, and ask them to confirm.

Not that it helps. I once spent a couple weeks and did 30 pages of UI 
design, showed it to the person in charge, had her initial each page as 
being right, and when the program was all done, she comes back with "OK, 
now let's work out what the screens should look like."  Hey, b___h, if I 
hadn't hardcoded the screens, I wouldn't be asking you to read them, now 
would I?  (And yes, everyone thought she was a b___h, but she was 
sleeping with the CEO, so...)

-- 
Darren New / San Diego, CA, USA (PST)

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Orchid XP v8 wrote:
>> What's wrong with "comp"?
> 
> Does that exist on Windoze?

Yes it does. In Unix it's "cmp".

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>> particular scenario, a basic file compare would be fine. (We would 
>> probably have to formally test the correctness of the compare program 
>> though!)
> 
> You could probably do that if you wrote it in Haskell. ;-)

I *have*, in fact, written such a program in Haskell. We're currently in 
the process of formally testing it. For something completely different, 
as it happens...

(And yes, it had a bug. I forgot to open the files in binary mode, so it 
was doing line end conversions. It also stopped processing the file when 
it reached a certain octet sequence. I wonder what other bugs we'll find?)

> Ask to clarify. Or guess, and ask them to confirm.
> 
> Not that it helps. I once spent a couple weeks and did 30 pages of UI 
> design, showed it to the person in charge, had her initial each page as 
> being right, and when the program was all done, she comes back with "OK, 
> now let's work out what the screens should look like."  Hey, b___h, if I 
> hadn't hardcoded the screens, I wouldn't be asking you to read them, now 
> would I?  (And yes, everyone thought she was a b___h, but she was 
> sleeping with the CEO, so...)

Damn. I'm not sleeping with anybody. :-(

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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>>> What's wrong with "comp"?
>> Does that exist on Windoze?
> 
> Yes it does. In Unix it's "cmp".

LOL! That great Unix tradition of eliding vowels at all costs...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Invisible wrote:
>>>> What's wrong with "comp"?
>>> Does that exist on Windoze?
>>
>> Yes it does. In Unix it's "cmp".
> 
> LOL! That great Unix tradition of eliding vowels at all costs...

along with the great Windows tradition of (a) picking different command 
flags for commands ported from UNIX, and (b) trying to make everything 
fit in 8.3 a decade after they got rid of that restriction in all their 
file systems.

-- 
Darren New / San Diego, CA, USA (PST)

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>> LOL! That great Unix tradition of eliding vowels at all costs...
> 
> along with the great Windows tradition of (a) picking different command 
> flags for commands ported from UNIX

I just love the way that you have to write a short Prolog program to 
discover the behaviour of most Unix commands for each given combination 
of switches.

(E.g., "-s" implies "-v" and "-c". "-k" disabled "-s". "-Q" reverses the 
sense of "-s". If "-L" is present then "-s" now controls something 
completely different. And if it's a Tuesday today then the "-R" switch 
is no-op...)

> (b) trying to make everything 
> fit in 8.3 a decade after they got rid of that restriction in all their 
> file systems.

Yeah, WTF is *that* about??

And *why* are there still programs who's installers and splash screens 
show up in dithered 256-colour or even 16-colour graphics when the 
entire civilized world has had 24-bit colour for a decade now?

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Invisible wrote:

> 
> And *why* are there still programs who's installers and splash screens 
> show up in dithered 256-colour or even 16-colour graphics when the 
> entire civilized world has had 24-bit colour for a decade now?
> 

It's an in-joke among the people who write installers. They laugh 
everytime someone says "Installers need more colors"

;)

Seriously, they're probably using an old version of installshield, or 
its in some ancient style guide somewhere ...

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*sigh*

The document has been extensively revised, and all the comments have 
vanished from it. Trouble is, it still contains the same mistakes. In 
fact, it even adds a few new ones! (E.g., on a bank holiday, don't just 
skip the tape that would have run, make the whole of the rest of the 
sequence slide backwards by one day instead.)

I give up...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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On Fri, 15 Aug 2008 10:22:30 +0100, Invisible wrote:

> *sigh*
> 
> The document has been extensively revised, and all the comments have
> vanished from it. Trouble is, it still contains the same mistakes. In
> fact, it even adds a few new ones! (E.g., on a bank holiday, don't just
> skip the tape that would have run, make the whole of the rest of the
> sequence slide backwards by one day instead.)
> 
> I give up...

Anything that would be considered illegal?

Jim

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