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....
-----Original Message-----
From: Legato NetWorker discussion
[mailto:NETWORKER AT listserv.temple DOT edu]On Behalf Of Tim Mooney
Sent: Tuesday, 20 December 2005 8:49 AM
To: NETWORKER AT listserv.temple DOT edu
Subject: Re: [Networker] any tips for backing up enormous sparse files?
In regard to: Re: [Networker] any tips for backing up enormous
sparse...:
> These are holey files according to uasm ?
>
> " holey
> The holey ASM handles holes or blocks of zeros when
> backing up files and preserves these holes during
> recovery. On some filesystems interfaces can be used
> to find out the location of file hole information.
> Otherwise, blocks of zeros that are read from the file
> are skipped. This ASM is normally applied automatically
> and does not need not be specified."
>
> It sounds to me like networker applies this directive automatically
but
> needs to read all the blocks of 0 but not transfer them. Not sure
what
> the point is then.. Perhaps try specifying this directive anyway.
Thanks for pointing out this directive. I didn't know about it.
I tried setting it explicitly, and it doesn't appear to have made any
difference. I had other directives in the .nsr file that were noticed
and acted upon, so I believe my .nsr file was correct.
In this particular case, we can probably get by with running the
"lastlog"
command, dumping the output to a file, and then skipping the real
lastlog
file. That works in this case, but won't work in general for large
sparse
files.
Thanks,
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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