On Thu, Jul 08, 2004 at 08:50:17AM -0400, Joshua Baker-LePain wrote: > On Thu, 8 Jul 2004 at 8:35am, Gene Heskett wrote > > > On Thursday 08 July 2004 01:32, Alexey I. Froloff wrote: > > >* Alexey I. Froloff <raorn@> [040707 14:10]: > > >> P.S. Right now I figured how to turn HW compression off (with mt > > >> utility) and started amtapetype again... > > > > > >Thanks to all for your help. amtapetype finished successfully. > > > > > >$ /usr/sbin/amtapetype -e 100g -f /dev/nst0 -t "HP-C7971A" > > >Writing 1024 Mbyte compresseable data: 25 sec > > >Writing 1024 Mbyte uncompresseable data: 72 sec > > >WARNING: Tape drive has hardware compression enabled > > > > Please disable this as it hides the true tapesize from amtapetype AND > > amanda. amanda can do a much better job of filling up a tape if > > amanda knows how much a tape can hold. ... > > Actually Gene, for this drive disabling hardware compression isn't > necessary. It's an LTO/Ultrium drive, and those are actually smart enough > to not compress already compressed data. Notice (below) how he still gets > the full 100GB native capacity? With those drives, you get the best of > both worlds -- you can mix software and hardware compression. Very, very > slick. >
Gene's second point is still valid though. What is the actual "real world data" capacity of the tape? Amanda will think 100GB and yet the HW compressor will be shrinking that 0-80% depending on the data compressability. So running tapetype if you plan to use HW compression is basically a time-waster as you will be guess-timating the actual data capacity anyway. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road (609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)
