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Re: Problem understanding tape_splitsize and runtapes
2007-06-12 05:38:03
Hi,
Sebastian Marten schrieb:
Hello list,
I have a problem understanding the coherence between tape_splitsize
and runtapes.
Runtapes tells amanda how many tapes she is maximum allowed to use in a single
run. If you plan to backup more data that fits on one tape, then you have to
set this value higher that "1".
Normally amanda saves full DLEs to a tape until it`s full. But if you have a
30 GB tape and amanda should backup 2x 20 GB, then 10 GB will stay unused on
the first tape. When you use tape_splitsize, you can get a better usage of the
tapes. Most of my tapes are filled between 95-99% since this option is available.
See manpage amanda.conf(5):
tape_splitsize
Default: none. Split dump file on tape into pieces of a specified size. This
allows dumps to be spread across multiple tapes, and can potentially make more
efficient use of tape space. Note that if this value is too large (more than
half the size of the average dump being split), substantial tape space can be
wasted. If too small, large dumps will be split into innumerable tiny
dumpfiles, adding to restoration complexity. A good rule of thumb, usually, is
1/10 of the size of your tape.
runtapes
Default: 1. The maximum number of tapes used in a single run. If a tape
changer is not configured, this option is not used and should be commented out
of the configuration file. If a tape changer is configured, this may be set
larger than one to let AMANDA write to more than one tape. Note that this is
an upper bound on the number of tapes, and AMANDA may use less. Also note that
as of this release, AMANDA does not support true tape overflow. When it
reaches the end of one tape, the backup image AMANDA was processing starts
over again on the next tape.
Now the problem:
if i try amdump test with runtapes = 1 the following error appears :
FAILURE AND STRANGE DUMP SUMMARY:
server /etc lev 0 FAILED [dump larger than available tape space,
38620 KB, but cannot incremental dump new disk]
planner: FATAL cannot fit anything on tape, bailing out
The problem is, you have only one tape (runtapes=1) available for each run. A
full dump have 48MB and your tape is only 30MB. You get this error, because
amanda can`t do a incremental dump, because she never did a full one (and
never can do, because only one tape is available and that one is too small).
Regards
Marc
--
Marc Muehlfeld (Leitung Systemadministration)
Zentrum fuer Humangenetik und Laboratoriumsmedizin Dr. Klein und Dr. Rost
Lochhamer Str. 29 - D-82152 Martinsried
Telefon: +49(0)89/895578-0 - Fax: +49(0)89/895578-78
http://www.medizinische-genetik.de
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