On Thursday 07 September 2006 23:20, Ryan Novosielski wrote: > Martin Simmons wrote: > >>>>>> On Wed, 06 Sep 2006 16:48:18 -0400, Ryan Novosielski said: > >> I have a question about my DDS4 drive... > >> > >> I have been backing up a 20GB FS with a DDS4 drive for quite some time. > >> The filesystem has been getting increasingly full, and until recently > >> was only 75% or so. I've reached 95% and my backup now exceeds one tape. > >> The estimated backup size is 19.766GB. > >> > >> However, my DDS4 drive is reporting tapes full at roughly 17.8GB. > >> Hardware compression is presumably enabled (I'm writing to /dev/rmt/1cbn > >> on a Solaris box). I'd like to check somehow, but am not sure how to do so. > > > > Maybe the 'mt status' shell command will print it? You need to unmount the > > drive from Bacula first. > > I downloaded 'mtx' and ran tapeinfo. Compression is apparently enabled. > However, any run says no tape is in the drive even if one is. > > >> I know a lot of the data is uncompressable, but wouldn't that make the > >> data larger (ie. the data will hit the capacity of the drive and request > >> a new tape), not make less fit on a tape? > > > > If the data is larger, then less fits on a tape :-) > > > > Remember that "larger" here means that the crappy expanding DDS4 compression > > has caused more bits to be written to the tape than were written to the drive > > by Bacula. Hence Bacula writes 17.8GB, which expands to more than 20GB (the > > tape capacity) on the tape. > > Ah, this may be the key here. I will try using no compression -- I would > expect to see 20GB or thereabouts fit on a tape afterwards. I have to > make sure that it is actually writing uncompressed though. > > >> Any hints for what to try here? I am formatting the tape now to make > >> sure that the capacity is correct (though this idea may be a holdover > >> from when I was using DLT's, which seemed to be forward and backward > >> compatible). > >> > >> If I am formatting /dev/rmt/1 instead of 1cbn, does that somehow turn > >> off compression? > > > > You probably want to use /dev/rmt/1bn to get the other flags correct. > > See man st. > > OK, I'm re-running my backup now with 1bn after doing some other testing > to try to get to the bottom of this. It appears that a fill test only > writes about 17GB too... I don't know what kind of data a 'bfill' does.
Shuffled random data. > > -- > ---- _ _ _ _ ___ _ _ _ > |Y#| | | |\/| | \ |\ | | |Ryan Novosielski - Systems Programmer III > |$&| |__| | | |__/ | \| _| |[EMAIL PROTECTED] - 973/972.0922 (2-0922) > \__/ Univ. of Med. and Dent.|IST/AST - NJMS Medical Science Bldg - C630 > > > ------------------------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 > _______________________________________________ > Bacula-users mailing list > Bacula-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bacula-users > ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
