Even though Networker might support DAR, does OnTap?

I did some research on this a while back (so my info may be dated), but my understanding is this:

The backup server initiates the NDMP command to the Filer (or other NDMP device), the OS on that device then begins to send data to tape by using means that it is aware of.  In the case of OnTap, it uses the typical Unix dump command. 

With dump/restore, there is no index created, thus, to recover, one has to scan from the beginning of tape of the first  tape in the dump set until the data is found (on whatever tape).  And the user waiting for the file will likely hope that their file is closer to the first part of the first tape rather than the last part of the last tape.

Netbackup & Networker will have an index knowing which NDMP tape set that a file is on, but I would guess that they would have no idea as to which tape in the set it is - or where on that tape (set: being number of tapes for that night's incremental, full, whatever).

If I'm off base, please clarify.

Thanks,

Jim Surlow
CSG Systems

-----Original Message-----
From: Alfred Lim [mailto:alfred@ptc.net]
Sent: Thursday, April 04, 2002 10:23 AM
To: toasters@mathworks.com
Subject: Re: One more netbackup question...

Well one thing for Legato Networker,
it support NDMP V3 and have this DAR feature.

-----Original Message-----
From: "Jeff Kennedy" <jlkennedy@amcc.com>
To: Don.Hickey@alcatel.com
Date: Thu, 04 Apr 2002 08:56:46 -0800
Subject: Re: One more netbackup question...

> Get a new backup software?  The problem is that some vendors do not
> support Direct Access Restore, meaning it will search through every tape
> starting at the first and scan the whole thing.  If no DAR, you're
> basically bummed.
>
> Do you use snapshots?  If you have the space it is a life-saver at
> times.
>
> ~JK
>
> Don.Hickey@alcatel.com wrote:
> >
> > I find restoring from a tape extraordinarly slowwwww.  I have home
> > directories on a clustered pair of F840 running 6.1.1r2.  I have
> > several volumes at about 300gb usable.  When I need to restore a file
> > from a users directory it can take up to 6+ hours (DLT 8000).   It
> > appears most of the time is taken searching for the files...  is there
> > anything you can suggest (including any white papers) to speed up this
> > process?
> >
> > thanks again
> >
> > Don
>
> --
> =====================
> Jeff Kennedy
> Unix Administrator
> AMCC
> jlkennedy@amcc.com