Using both hardware and software compression will generally result in less tape capacity, because compressed data doesn't compress well.
There have been many good discussions of the tradeoffs between software and hardware compression with AMANDA. I would suggest searching the archives. > -----Original Message----- > From: Dengfeng Liu [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, January 09, 2002 4:40 PM > To: [EMAIL PROTECTED] > Subject: compression and tape capacity.. > > > Hi, > > Can anyone here tell me the difference of software > compression,hardware > compression and tape capacity? > For example, I have a sony AIT2 autoloader(can anyone give a chg-scsi > configuration file?),which have 50GB(native)/100GB(compress) > mark on it. > also, the autoloader have a hardware compression switch.If in my > amanda.conf file I use compress high,then the tape can hold > 100GB tar.gz > file of the amanda output?if the software compression ratio > is 30%,then > can I run a backup of a file system size of 140GB if I open > the hardware > compression switch? > In one word, I am totally confused with the > 50GB(native)/100GB on the tape > and the compression option in amanda.conf. > > Any hints? > Dengfeng >
