My configuration:
zorn->[8] > amadmin daily version
build: VERSION="Amanda-2.5.2-20070530"
BUILT_DATE="Thu May 31 09:14:26 EDT 2007"
BUILT_MACH="SunOS zorn.math.purdue.edu 5.10 Generic_118833-03 sun4u
sparc SUNW,Sun-Fire-280R"
CC="/pkgs/gcc-3.4.3/bin/gcc"
CONFIGURE_COMMAND="'./configure' 'CC=/pkgs/gcc-3.4.3/bin/gcc'
'MT=/opt/csw/bin/mt' 'MTF=-f' 'MTX=/opt/csw/sbin/mtx'
'PERL=/opt/csw/bin/perl' '--prefix=/local/Amanda/amanda-2.5.2-20070530'
'--with-user=amanda' '--with-group=operator'
'--with-gnutar=/opt/csw/bin/gtar'
'--with-gnutar-listdir=/var/amanda/gnutar-lists'
'--with-includes=/opt/csw/include' '--with-libraries=/opt/csw/lib'
'--with-index-server=zorn' '--with-smbclient=/pkgs/samba/bin/smbclient'
'--with-tape-device=/dev/rmt/1bn' '--with-changer-device=/dev/changer/1'
'--with-maxtapeblocksize=2048'"
My tape unit is a Sun C4 38 slot and 1 LTO2 tape drive. My tapetype is
defined as followed
define tapetype LTO2-HWC {
comment "LTO-2-Hardware Compression on."
blocksize 1024 kbytes
length 300000 mbytes #200G
filemark 0 kbytes
speed 27315 kps #27 Mb/s
}
"length 300000 mbytes" was calculated by 1.5 times the actual size of 200GB.
Up to now my dumptype has had compress equal to none. I decided to let the
hardware do the compression work. The problem with this is the calculation
of the length is just a guess and seems to cause problems when trying to fit
files on the tape. In some cases amanda thinks it has more tape than it
really does so it tries to write a bigger file to the last part of the tape
and fails.
I am thinking of changing my setup to do software compression and see if
this will give me better tape usage.
Q1) I have asked Sun and the makers of the LTO2 drive and it seems there is
no way to turn hardware compression on or off on this unit, it is always on.
>From my reading in the Amanda forum it seems that the LTO2 drive will sense
if the data is compressed and turn off hardware compression if the data is
already compressed. Is this correct?
Q2) Any suggestions, pros or cons in going this direction? I guess the trade
off is that I would get better tape usage at the expense of compute time to
do the software compression.
Q3) From the config.log it seems the default program for compression is gzip
and it uses -fast or -best. From gzip man page it says I can use -#x where x
is between 1 (fast) 9 (best). Is there a way to set the compress number
without having to use the "compress server custom"?
Thanks
Robert
_____________________________________________________________________
Robert P. McGraw, Jr.
Manager, Computer System EMAIL: [EMAIL PROTECTED]
Purdue University ROOM: MATH-807
Department of Mathematics PHONE: (765) 494-6055
150 N. University Street FAX: (419) 821-0540
West Lafayette, IN 47907-2067
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