On Mon, Sep 04, 2006 at 03:11:14PM -0700, Mike Leo wrote:
i have a 35/70Gb DLT drive with IV tapes, but I am only getting less than 30 gigs' per tape.
my bacula-sd.conf lists " Media Type = DLT"....if this is not accurate, could bacula think I have only a 15/30Gb drive? Should it read DTL7000 or something?
Bacula doesn't actually parse the media type - it's nothing more than a unique identifier string that bacula uses to determine what volumes can be read by what drives. You could call file volumes "blue", DLT tapes "red", and DVDRs "green" and it would work fine. Bacula doesn't try to pre-determine the amount of space available on a tape. It just writes until the drive reports that it's hit the end of media, re-reads the last succesfully written block to make sure it got there okay, marks the volume full and asks for another one. The fact that you're getting about 30G of data per tape implies that you have hardware tape compression off. I believe the 'mt' command will tell you the compression status - the online manual has an example. The other 5G or so is probably taken up by volume metadata, such as the volume label and file attributes.
Also, does bacula compress naturally or do i have to tell it too?
No, you have to explicitly enable gzip compression if you want to use it. It's typically reccomended to use drive hardware compression instead, though, as a) drive hardware compression is usually faster, especially on older machines, and b) it's possible to run into file daemon incompatabilities that can make it difficult to restore data, especially if you're trying to restore the data onto a different machine that the one it was backed up on. -- Frank Sweetser fs at wpi.edu | For every problem, there is a solution that WPI Network Engineer | is simple, elegant, and wrong. - HL Mencken GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 8CEC