On Wed, Aug 01, 2007 at 04:52:01AM +0200, Ralf Auer wrote:
> Hi everybody,
>
> I have a question that is related to that 'friday tape question' in
> Amanda's Top10 I quoted below:
>
> /*
> Imagine that you have your classic backup-schedule running fine.
> Everything is calculated and designed well, so your tape gets filled
> well each night.
> Now one user generates an unforeseen huge amount of data. For example,
> he duplicates one big data-directory by mistake.
> So the size of the directory raises within one day, maybe for multiple GBs.
> Would your classic backup-scheme catch that? Or would it run out of
> tape, simply because it was not calculated to have that filesystem with
> that size?
> Amanda would try to catch it (and most of the time succeed ...).
> */
>
> What, if it does NOT succeed? For example, I run out of free tapes
> unexpectedly early?
>
> Do I get a notification, or do I loose data?
>
>
> Example:
> Let's assume, I have 5 clients to backup, my tapecycle is 5, my dumpcyle
> is 3 and runspercycle is 5. I have all 5 tapes in my autochanger.
> On Monday, clients 'U' & 'V' are in the full backup. On Tuesday, client
> 'W' is in full backup and during the day some user produces so much
> data, that for Wednesday-Backup all three remaining tapes are used.
> Then, there is no tape left to hold the still pending full backups for
> clients 'X' and 'Y' on Thursday or Friday...
>
>
> The optimum would be an email after Wendnesday, that tells me that I
> have to buy more tapes. The worst thing would be, that Amanda tapes over
> the 'U & V' full backup tape for the 'X' and 'Y' backups.
>
> So, can you tell me, what will happen in this case? Can I rely on not
> loosing data, just because some user wrote an infinite loop in his
> MonteCarlo program producing GBs of data?
>
>
What is this, trolling for arguments against amanda usage?
How/why are you running 5 amdumps (runs per cycle)
with only a 3 day dump cycle?
Oh, was that a mistype, it should have been a 5 day dumpcycle?
Then why does your number of tapes in rotation exactly match
the runspercycle when the recommended is 2-4 times that?
Why with such a tight setup do you have runtapes set to
greater than 1. With only 1 tape allowed per day you would
have gotten a failure to backup that DLE that did not fit.
This would have been noticed by amanda during the estimate
phase, before the dump started and noted in the report.
Even without the staged situation, amanda would have told
you after one dumpcycle that you were about to overwrite
your only full backup of <insert a DLE name> notifying
you of the need for more tapes.
You only have one DLE per client? Very unusual. But
that is the only reason I'd see amanda choosing to do a
full backup of exactly one client on each day of a dumpcycle.
Or are you artificially forcing the desired full dumps?
--
Jon H. LaBadie jon AT jgcomp DOT com
JG Computing
4455 Province Line Road (609) 252-0159
Princeton, NJ 08540-4322 (609) 683-7220 (fax)
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