ADSM-L

Re: unix sparse file backup?

2005-01-25 17:35:44
Subject: Re: unix sparse file backup?
From: Alexander Lazarevich <alazarev AT ITG.UIUC DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Tue, 25 Jan 2005 16:35:29 -0600
Okay I'm with you so far, but will TSM server be able to tag a file as
a sparse file even if the client is compressing the file before it
sends it to TSM? Or does the client mark it as a sparse file. Otherwise
how would makesparsefile know to restore the file as a sparse file?

Thanks!

Alex

On Tue, 25 Jan 2005, Andrew Raibeck wrote:

With Unix, I think it is difficult to determine during backup whether the
file is sparse or not, since there aren't any flags that say "I'm a sparse
file, here is allocation map". My understanding is that during restore,
TSM analyzes the data for lengthy patterns of zeroes in the data stream,
and that is how MAKESPARSEFILE works; but TSM does not do that analysis
during the backup.

Try using client compression, as a very sparse file should compress very
well.

Regards,

Andy

Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: storman AT us.ibm DOT com

The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.

"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 01/25/2005
09:53:12:

TSM 5.1.9.0 on windows 2K server.

We have a new Fedora Core 3 64-bit client, which has a /var/log/lastlog
sparse file on it, which is 1.2TB, yet only 112K in real blocks used.
TSM
is trying to backup the entire 1.2TB file, which is causing some backup
problems.

I've never had this issue before so I looked up sparse files in the UNIX
users guide, and it says sparse files can be "restored" or "retrieved"
with or without the block holes in it using the makesparsefile option in
dsm.opt. However, it does not say if this applys to the backup.

I looked on my another unix client, and it's /var/log/lastlog is 19MB
but
only 276 in actual blocks, yet TSM backed it up as 19MB. So it seems
that
TSM must backup sparse files WITH the empty data holes in it, and only
has
the option to restore without the holes.

Is this correct?

On the other hand, anyone else have a FC3, and seen huge TB sized
lastlog
files? That seems way out of hand.

Thanks in advance,

Alex
-----                                                            -----
   Alex Lazarevich | Systems Administrator | Imaging Technology Group
     Beckman Institute | University of Illinois | www.itg.uiuc.edu
                405 North Mathews Avenue Urbana IL 61801
            Ph: (217) 244-1565 | Email: alazarev AT itg.uiuc DOT edu
-----                                                            -----


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