The data you're backing up has *everything* to do with real-world 
compression.  To contrast the 4x we see with Oracle, our file server 
backups are typically in the 1.5x - 1.75x compression range.  It even 
varies from tape to tape within a single full backup job.  Our main file 
servers take something like 22 LTO-2 tapes for a full backup.  Some tapes 
in that job will have almost no compression while others could see up to 
2x - it all depends on the characteristics of the data they contain.

Jeff Mery - MCSE, MCP
National Instruments

-------------------------------------------------------------------------
"Allow me to extol the virtues of the Net Fairy, and of all the fantastic
dorks that make the nice packets go from here to there. Amen."
TB - Penny Arcade
-------------------------------------------------------------------------



Tim Verbois <Tim.Verbois AT ET.VLAANDEREN DOT BE> 
Sent by: Legato NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>
04/05/2006 12:49 AM
Please respond to
Legato NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>; Please 
respond to
Tim Verbois <Tim.Verbois AT ET.VLAANDEREN DOT BE>


To
NETWORKER AT LISTSERV.TEMPLE DOT EDU
cc

Subject
Re: [Networker] 1.2TB LTO3?






 729 GB BRO394
 744 GB BRO772
 749 GB BRO386
 766 GB BRO734
 778 GB BRO659
 794 GB BRO722
 796 GB BRO512
 822 GB BRO695

These are LTO-2 tapes, without compression they store 200 GB.  We have
an imap mail server, a lot of small text files.

The possible compression depends on the sort of data, so maybe you don't
have data that can be compressed a lot?


Jeff Mery wrote:

>I can't speak directly to LTO-3, but we've seen almost 4x compression on 
>our LTO-2 with our larger Oracle databases.  (Networker 7.1.4 on Solaris 
9 
>w/ FC-native LTO-2 drives)
>
>Jeff Mery - MCSE, MCP
>National Instruments
>
>-------------------------------------------------------------------------
>"Allow me to extol the virtues of the Net Fairy, and of all the fantastic
>dorks that make the nice packets go from here to there. Amen."
>TB - Penny Arcade
>-------------------------------------------------------------------------
>
>
>
>Dave Mussulman <mussulma AT UIUC DOT EDU> 
>Sent by: Legato NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>
>04/04/2006 08:57 AM
>Please respond to
>Legato NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>; Please 
>respond to
>Dave Mussulman <mussulma AT UIUC DOT EDU>
>
>
>To
>NETWORKER AT LISTSERV.TEMPLE DOT EDU
>cc
>
>Subject
>[Networker] 1.2TB LTO3?
>
>
>
>
>
>
>I got a sales flyer in the mail today for an LTO-3 Ultrium drive that
>does 1.2TB/tape and 160MB/s.  In our environment, I've seen our drives
>stream at near 160MB/s, but I've never seen any of our tapes get the 3x
>compression 1.2TB offers.  Scanning through the library, I'd say our
>average is around 650GB/tape with a few in the 750GB area.
>
>Is it just my data, and are other groups seeing more than 2x
>compression?  Anything close to 3x?
>
>Dave
>
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>

-- 
Tim Verbois
EDS-Telindus
Unix Team
02/553.71.73

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