On 2006-07-03 09:34, Cyrille Bollu wrote:
Jon LaBadie <jon AT jgcomp DOT com> a écrit sur 30/06/2006 15:47:24 :
> > Sorry for asking but, why do you say backuping directly to tape is
slow?
> >
> > I guess he's doing local backups (ie: The 700GB are not sent over the
> > network every full backups).
> >
> > In this configuration what would be the benefit of having an
holding disk?
> >
>
> See my note about his writing 80000 tiny tape files.
>
This is correctly handled by Amanda when the "holdingdisk no" variable
is set:
Here's an extract from one of my amanda report:
taper: tape daily-backup04 kb 181855648 fm 23 [OK]
(with 23 DLE)
But in this case you will be completely bypassing the holdingdisk!
The backup process on the client (tar/dump + client gzip) is
then connected with a TCP stream to the taper command. (
That also means that your tape drive is now working at the speed
that tar/dump+gzip+network can generate.
Is this the cause of your tape drive's shoe-shining problem?
Using a dumptype for with "tape_splitsize" AND a large
"split_diskbuffer" will now at least buffer one chunk on the disk
and write that chunk on tape at a speed of
min(holdingdiskspeed, tapedrivespeed).
--
Paul Bijnens, xplanation Technology Services 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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