> On Nov 30, 2018, at 3:45 AM, Stefan G. Weichinger <s...@amanda.org> wrote:
>
> Am 28.11.18 um 20:24 schrieb Debra S Baddorf:
>
>> Not sure if these paragraphs are still in the example config files or not;
>> I’ve hung onto them because they
>> were so useful. In case they help you:
>
> [..]
>
> thanks for sharing that, this somehow corresponds to a task I am
> starting over the weekend:
>
> at a customer we backup around 16 TB to LTO6 tapes in a 8-slot changer.
> Bit of balancing needed in normal daily runs ... I let amanda skip some
> bigger chunks on days 1-4 and do these on weekends, for example.
>
> The quality management there requests that we/I create (a set of)
> archive tapes at the end of the year, and these should be WORM tapes.
>
> So the goal is to get lev0 backups of all DLEs into one single run.
>
> I fiddled with amvault last year or so, then edited the mention
> threshold parameters to collect lev0-backups in the holding disk to
> prepare that one big amflush to WORM tapes.
>
> Not to mention that the problem is to not waste WORM tapes ...
>
>
> Today I reattack all this and add 10 RW-tapes to my config "archive",
> share the disklist and let amanda do backups of that for a while to
> prepare things.
>
> Suggestions and ideas welcome.
Well, from comp sci courses 20 years ago, the best algorithm to fill the tapes
(or the “Bag” in CS class)
is the Greedy Method. Which is also the most obvious one.
taperalgo=largestfit
I.E. Pick the biggest thing that will still fit in the bag.
Repeat.
(Physical example: put the large stones in the jar first. Then medium, then
small pebbles.
Then sand, then water. Used in life-strategy classes. Determine what matters
most to you, do it first.)
To do this, you need to have a large choice of DLE’s dumped into your holding
disk, before amanda
starts putting them to tape. So it can find the most optimal “biggest, then
next biggest, then ….. “
So you want to have lots of DLE’s on disk before taping starts.
IFF you have the holding disk space, you might want these params:
flush-threshold-dumped 300 # (or perhaps only 150) ## I have NOT
tested this one
flush-threshold-scheduled 100 #
###However, all dumps will be flushed; none will
### be left on the holding disk.
taperflush 0
autoflush yes
taperalgo largestfit
dump order “SsSsSs” # so that it accumulates a bunch of small ones, as well
as big ones,
# for the Greedy Algorithm to choose from
If the archives are going offsite, and are not available for daily file
recoveries, you may want
to set "record no” so that normal dailes don’t base their level 1’s off
THIS level 0.
(I do this, for my archive runs.)
And of course, you prefix the run with
amadmin config force *
(I seem to need amadmin config force *.restof.siteAddress Try and see)
I do these once a month, but have never worried about the tape filling, very
much.
Beyond always using “largestfit” and having some DLE’s on disk before
taping starts.
If you are using a lot of tapes (you are) it might be worth fiddling with.
Deb Baddorf
Fermilab
