Hello!

Jon H. LaBadie wrote:

> On Mon, Nov 04, 2002 at 03:04:27PM +0100, Patrick M. Hausen wrote:
> > 
> > So my question is: does a holding-disk speed up this process? I mean,
> > Amanda will start a dumper on the filesystem that starts filling
> > the holding-disk. At the same time (?) a taper will start wrtiting
> > the holding-disk's contents to tape. Now imagine the dumper getting
> > to slow for the tape ... the holding-disk won't be filled quick
> > enough either. Then there's a lot of seeks on the holding-disk
> > itself, if it's read and written at the same time.
> > 
> > Or is the mental picture I have about Amanda's operation incorrect?
> 
> yes, incorrect.
> 
> nothing goes from holding disk to tape unless the dump to holding disk
> has finished.  Then it goes like cat'ting or dd'ing to tape.  Small
> likelyhood of too slow for tape.

Aggreed - cat/dd >/dev/tape will surely be fast enough.
But I need a holding disk at least as large as my largest FS to dump?
So if I have one 170 GB RAID I need one 170 GB holding disk?

The customer won't like that ;-)

Or is this what the chunksize parameter is for - taper will start when
the first chunk is completely written to the holding disk?

In this case I'm sure a holding disk will speed up things quite a
bit even in my "pathological" case of only one big FS.
A little bit of tape stop-and-go between chunks won't hurt as much
as the current configuration does.


Thanks,

Patrick M. Hausen
Technical Director
-- 
punkt.de GmbH         Internet - Dienstleistungen - Beratung
Scheffelstr. 17 a     Tel. 0721 9109 -0 Fax: -100
76135 Karlsruhe       http://punkt.de