Networker

Re: [Networker] 600GB saved on single LTO volume??

2003-01-23 14:32:03
Subject: Re: [Networker] 600GB saved on single LTO volume??
From: George Sinclair <George.Sinclair AT NOAA DOT GOV>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Thu, 23 Jan 2003 14:40:50 -0500
I got to thinking about this. Is it possible that if you're cramming as
much data as possible to the tape drives -- well, I guess streaming --
then because there's more data in the buffer, the drives might be able
to do a better job compressing the data? For example, let's suppose I
had 3 sessions running from one host, but I'm not pushing the drive to
the full speed it can do even though it is reasonably compressible data.
Next, I send more sessions from another host. Now, the drive is maxed,
and the buffer is really full, providing more data and maybe as a result
a bigger amount of compressible data? Does NetWorker differentiate
between which streams are being compressed, or does it wrap it all
together and then compress that? If it's the later, then it would make
sense that buffering more data would produce better compression.

George

roger midway wrote:
>
> Thanks for the positive responses.  I will clone a
> volume or two and do several spot recovers.
>
> RM
> --- Tim Mooney <mooney AT dogbert.cc.ndsu.NoDak DOT edu>
> wrote:
> > In regard to: [Networker] 600GB saved on single LTO
> > volume??, roger midway...:
> >
> > >Would anyone consider it odd for 600gb to be store
> > to
> > >a single LTO volume.  I ran backups of several SUN
> > >systems and was amazed (and concerned) that there
> > was
> > >upwards of 600gb save to muliple LTO tapes.  This
> > was
> > >a localized backup.
> > >
> > >What do you think?
> > >
> > >SEAGATE LTO Ultrium 1
> > >SUN Solaris
> > >NetWorker 6.1.2
> >
> > I think you have very compressable data and you're
> > getting the data
> > to your drives fast enough (easier since it's local)
> > that your drives
> > are never kept waiting.
> >
> > This fall our site upgraded from DLT7000 to
> > SuperDLT1 -- we were badly
> > in need of more capacity.  The first few tapes we
> > had that filled at 170+
> > Gig made me smile, but we've had a couple tapes
> > since that have gone over
> > 370 or 400 Gig, and *that* makes my management
> > smile.
> >
> > In short: rejoice and be happy (but clone the volume
> > or do a few spot
> > recovers from it, for your own peace of mind).  :-)
> >
> > Tim
> > --
> > Tim Mooney
> > mooney AT dogbert.cc.ndsu.NoDak DOT edu
> > Information Technology Services         (701)
> > 231-1076 (Voice)
> > Room 242-J6, IACC Building              (701)
> > 231-8541 (Fax)
> > North Dakota State University, Fargo, ND 58105-5164
>
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