On Sat, 25 Nov 2006 13:00:00 +0100, you wrote: >On Saturday 25 November 2006 12:13, Peter Crighton wrote:
>> I tried tar cvf /dev/nst0 file, with a 32MB file and the tape drive >> ran continuously for 40s, which is about 800kb/s. > >Read the tape back with dd, which should allow you to determine the block size >that tar used. In fact, if you do an strace on tar, you will see *exactly* >what it is doing, and you can simply duplicate it in Bacula. It is possible, >but I will be very surprised if it is writing in 512 byte chunks. > OK, with the command dd of=/home/root/test/tape count=1 </dev/nst0 I end up with a file called tape of size 512, so I believe that tar is writing 512 byte blocks, but doing so continuously rather than repeatedly stopping. Out of interest and despite not having completed the fill test in btape, I have initiated a backup using bconsole. 35MB were backed up in approx 8 minutes, equating to the 70kb/s that I see with btape (and confirming to me that the tape is accessed in a bursty fashion within bacula as I expected). The size is confirmed by using scanblocks in btape. Unless anyone can suggest an alternative setup for my existing tape drive, I guess now that my options are to accept the performance of this tape drive, use an alternative backup program, or buy a new (well second hand off Ebay) drive. What are the best alternative type of drive (it's for a home office so only requires a modest capability). Looking on Ebay DDS-3/DDS-4 drives and tapes are available at a reasonable cost, giving a comparable capacity to my current drive and probably almost a no-cost swap if I sell my existing drive and tapes on Ebay. -- Peter Crighton ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
