On Monday 19 May 2003 02:55, Richard Russell wrote:
><snip>
>
>> Because in amanda, they don't write to the tape drive. Other
>> programs do. There are several possible reasons, I'll
>> mention only one. How do you have 20 client hosts all
>> dumping simultaneously to the same tape drive and use those
>> program's multi-tape feature?
>
>Um.
>
>I thought Amanda got dump images from clients in parallel, and put
> them on the holding disk, and _then_ wrote these out to the tape,
> one at a time...
It does exactly that, unless there is no holding disk at all. But
in doing so, then tar has lost the ability to track whats been sent
to the tape, and therefore has no idea of how many bytes have been
sent to the media. Ditto for dump.
> I didn't think that the images were interleaved
> on tape. What does amanda use to write to tape? I *think* it uses
> dd, but can't quite tell... That would explain why it couldn't
> split backups across tapes. (Am I correct?)
>> > My problem is that I (am planning to) have a single
>>
>> filesystem, which
>>
>> > will be around 300Gb in size, but I have a choice between
>>
>> DLT4000 and
>>
>> > DLT7000 tapes, at 40 or 70Gb each. I guess I can do the
>> > work-around that Jon LaBadie mentioned later in the email I
>> > quoted
>>
>> above, but I'd
>>
>> > rather not, if I can avoid it. If I have no choice, then
>>
>> rather than
>>
>> > explicitly listing X different DLEs, I'd rather be able to
>>
>> say /BIG/*,
>>
>> > and have amanda figure out how best to order them. Is that
>> > possible?
>>
>> Lots of amanda users split according to the procedure I
>> outlined. My /BIG is only 40GB. But then my tape is onle
>> 12GB. I'm sorry it will be a "pain" to set up. Then again,
>> after the 5 minutes it took me to do it 3 years ago, I
>> haven't had to do anything about it since. That is a minor
>> part of the configuration.
>
>OK, it seems that perhaps I am carrying some Legato baggage with
> me. I'm new to amanda, you see. When I plan a backup system, I'm
> used to trying to do it in a regular fashion, say with a full
> dump of everything on the weekend, followed by daily
> incrementals. I'm used to being able to take my weekend tapes
> offsite as an offsite archive, so if everything burns down, I can
> go back to my most recent offsite tapeset, and restore everything
> from there, and get a consistent system.
>
>After reading a bit here, and some other doco, I think I might
> have discovered that my assumptions about amanda are slightly
> wrong. I suppose also, that my particular needs are slightly
> different to most peoples, in that I have (or will soon have) a
> single large data partition of around 200Gb, and it is likely to
> be on the same server that the tape robot is attached to.
>
>Anyway, it seems that what I need to do is use DLEs to split my
> big partition into sub-trees to back up, allow amanda to do its
> thing on a daily basis, perhaps, and then weekly, use a different
> amanda config (with the same disklist) to do a full dump, which i
> can then take home for offsite archive purposes.
Better yet, when you have it setup and running, simply box up the
last "dumpcycle" tapes and take them to secure storage on say
Monday's, bringing in the ones taken offsite the week before.
With 3 dumpcycles worth of tapes in the pool, you could leave 2 sets
of them offsite, a highly desirable condition, particularly if
there are 2 different offsite storage locations available.
This simplify's amanda's record-keeping immensely, and doesn't
require two seperate configurations, nor for you to recall exactly
what was where in which config. That can and will be (Murphy is
alive and well, thank you, I ran into him just yesterday morning),
a major PITA, only discovered when its too late.
Hopefully, unless the accountant is really trying to cover his
tracks, all 3 locations won't burn simultainiously. OTOH, the
accountant should NOT have accurate, uptodate knowledge of the
offsite location(s) ever. Thats just plain good CMA sense. A
little paranoia is a Good Thing(tm). :) FWIW, I've seen several
examples of that failure in my 68 years.
--
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz 512M
99.26% setiathome rank, not too shabby for a WV hillbilly
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by Gene Heskett are:
Copyright 2003 by Maurice Eugene Heskett, all rights reserved.
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