And meanwhile, just around the corner on the Internet, the o/s developers are 
talking about much the same issue, but they are in the position to do something 
about it...

It's about zfs... but it refers to solaris ufs having no special handling for 
sparse files... and suggests other o/s's need something added too...

http://blogs.sun.com/roller/page/bonwick?entry=seek_hole_and_seek_data




-----Original Message-----
From: Legato NetWorker discussion
[mailto:NETWORKER AT listserv.temple DOT edu]On Behalf Of Maarten Boot
(CWEU-USERS/CWNL)
Sent: Wednesday, 21 December 2005 8:26 PM
To: NETWORKER AT listserv.temple DOT edu
Subject: Re: [Networker] any tips for backing up enormous sparse files?


The dump or ufsdump on solaris works like that as it opens the raw disk for 
reading. 


On Tuesday 20 December 2005 20:38, Tim Mooney wrote:
> In regard to: RE: [Networker] any tips for backing up enormous sparse...:
> > on reading the manpage to the end, it says that you can't specify it
> > yourself. it just comes into play when the disk block count does not
> > match the byte size for a file...
> >
> > i have been reading up on sparse files.... unless the o/s (filesystem
> > provider) gives you a function to read only the real blocks of a sparse
> > file you have to read all the way through the file.... I can't find
> > anything specific in solaris, and if there is such a thing for linux
> > filesystems it may be that legato is not coded to use it....
>
> Thanks for the additional information on this!  I can't find any
> specific interface for this (I would expect it to be part of either the
> fcntl, open, or read system calls) on Linux either.
>
> I'm also guessing that you're correct about your last point too -- even
> if there is one, NetWorker probably isn't using it (yet).  If I discover
> there is some API for doing this, I'll report back.
>
> Tim
>
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-- 
Maarten Boot, 
Compuware Europe B.V.
Hoogoorddreef 5
1101 BA Amsterdam
Tel: +31 20 312 6511

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