Hello, On 6/12/2006 3:28 PM, Michel Meyers wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Andrea Soracchi wrote: > >>There are little GB of mpeg.... >> >>If I try to set compression off and backup 3 directory (all 555MB, no >>multimedia files) I get : >> >> VolBytes: 488,242,591 >> >> >>The same backup with compression on is: >> >> VolBytes: 488,242,591 >> >>The result is equal!!! >> >>Why? Compression is on or off? > > > We're talking hardware compression here, right? In that case, the > solution is simple, at least as far as I understand it (somebody correct > me if I'm wrong):
That doesn't seem necessary as far as I know... > Bacula doesn't know. Your drive does the compression, > Bacula only sends it the data uncompressed and that's why the values > don't change (it sends the very same amount of data, regardless of > whether your drive's hardware compression is on or off). > > Now, if you enabled software comprression, things would be different. In > that case, Bacula would be doing the compression and would know the > 'before' and 'after' sizes of the data. There is only one reliable way to find out if hardware compression is working if you don't trust the drives information, as can be determined with mt or tapeinfo: Try it. Load a tape, set compression to what you want - usually only on or off - and start filling the tape. Count how much data is written to tape. I typically do something like this: while dd if=/tmp/testdata bs=1M of=/dev/nstX ; do echo -en ; done mt -f /dev/nstX tell with testdata being a file with preloaded data, either well compressible (usually just some text file I've got lying around) or a dump of /dev/urandom of the necessary size. It's a good thing to make sure your test data is a multipple of the block size you use on that tape. Arno > Greetings, > Michel > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.2 (MingW32) - GPGrelay v0.959 > > iD8DBQFEjWwV2Vs+MkscAyURApuBAKDV221JY+myRHzt+g8O+/HQg46lSgCgzCN6 > Fu6XcOG7vLd6ZlzIPgf3oOo= > =cpk4 > -----END PGP SIGNATURE----- > > > _______________________________________________ > Bacula-users mailing list > Bacula-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bacula-users > -- IT-Service Lehmann [EMAIL PROTECTED] Arno Lehmann http://www.its-lehmann.de _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
