Chris Loken wrote:
Apologies if this has come up before. Couldn't find anything relevant.
I'm talking about level 0 dumps (not incrementals). Using ait-3 tapes,
GNUTAR (not linux "dump"), a tape library, 104GB holding disk and
setting runtapes greater than 1 (I need to dump several tapes-worth of
data). NO software or hardware compression. amanda-2.4.4p1-0.3E
Amanda works great for me. These are efficiency questions - not critical
problems.
a) When backing-up multiple disks from a single client, amanda seems to
dump and then write them to tape in order of increasing size. This can
be inefficient. e.g. if you have filesystems that are 40GB, 40GB, 55GB
and 55GB and write to 100GB tapes, amanda will use 3 tapes when the
backup would fit on 2 tapes.
b) amanda doesn't seem to know that it will run out of space on a tape.
E.g. if I have two 65GB filesystems to dump to a 100GB tape, amanda will
write the first and then start writing the second one and keep going
until it hits the end of tape. It then puts in the next tape and
rewrites which is great but a lot of time was wasted writing a file
which wasn't going to fit on the first tape. I'm running amtapetype for
myself right now but have been using a tape entry from the amanda faq
that sets "length 108890 mbytes" (but there are two different ones for
the same drive and tape; Sony SDX-700C and AIT-3).
So, my questions are 1) is what I've described above true (seems to be
for me) and 2) is there anything I can do (easily) to change this
behaviour?
Use the parameter "taperalgo largestfit".
But beware of some interaction with dumporder, inparallel and the
taperalgo:
http://marc.theaimsgroup.com/?l=amanda-users&m=106277015010167&w=2
About nr2: you can't change it, but it hurts less when the largestfit
algoritm is applied.
--
Paul Bijnens, Xplanation Tel +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM Fax +32 16 397.512
http://www.xplanation.com/ email: Paul.Bijnens AT xplanation DOT com
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