Hello,
There are different ways to handle compression, i prefer letting the
Hardware ( Tapes) handle it ( The utilities\program that comes with your
Tape Library or Device\driver will let you set the compression).
I would consider compression directive on the client when backing up over
WAN or using replication technologies.
Other concern is a server that is already slow with large amt of small
file will further slow down on backups while applying compression ( within
software) directive.
"Werth, Dave" <dave.werth AT GARMIN DOT COM>
Sent by: EMC NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>
02/25/2008 03:20 PM
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EMC NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>; Please respond
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"Werth, Dave" <dave.werth AT GARMIN DOT COM>
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Subject
Re: [Networker] Compression on Win2003 servers question
Michael,
The compressibility of data is pretty variable depending on what you're
backing up. Some things are very compressible and others are not. When
you turn on the compression directive in Networker it compresses the
data on the client before sending it to the server and so reports the
amount of compressed data it receives, not the original amount of data
uncompressed.
For instance I use the "NT with compression" directive on our main file
server. For the three large drives on the file server we get the
following results:
Networker Win Exp.
Compression%
E:\ 218GB 282GB
22.7%
F:\ 191GB 285GB
33.0%
G:\ 132GB 183GB
37.9%
The Networker column is what is reported on the SaveGroup Completion
report and the Windows Explorer column is from right clicking on the
drive letter and clicking Properties. I calculated the compression by
(W-N)/W where N is the Networker number and W in the Windows number,
hope that's the right way to do it.
Hope this helps.
Dave Werth
Garmin AT, Inc.
Salem, Oregon
-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of MIchael Leone
Sent: Monday, February 25, 2008 9:46 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] Compression on Win2003 servers question
I have a Win2003 server, NW 7.4 SP1, using an HP SDLT autoloader. Total
size of backup is about 600G (589G, according to mminfo). We'd like to
do
a full backup every day. However, I seem to be averaging 4 tapes (3 full
tapes, and 25% used on the last) every day. Now, an SDLT tape is 160G
native, up to 320G compressed, so 600G would need 4 tapes native (3 and
3/4 or so, according to the math).
IOW, it doesn't appear as if compression is being used, or just barely
used. I see nowhere in NW how to turn on hardware compression on the
autochanger. Am I just missing it?
I did change to using the "NT with compression" directive, which didn't
seem to affect the output; I am still getting 3.25 tapes per day used.
My question: I am backing up 3 servers, 2 of which were set to use the
compression directive, and 1 was not (this last server is very small,
and
doesn't significantly add to the total). Do all group members need to
use
the same compression directive, else NW won't compress? It shouldn't be
a
problem to make all 3 servers use the compression directive, but I
thought
I could use it only on the server that needs it (one server accounts for
about 570G of the 590G total).
Thanks
--
Michael Leone
Network Administrator, ISM
Philadelphia Housing Authority
2500 Jackson St
Philadelphia, PA 19145
Tel: 215-684-4180
Cell: 215-252-0143
<mailto:michael.leone AT pha.phila DOT gov>
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