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
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