> > to get the maximum speed with your LTO-5 drive you should enable data > spooling and change the "Maximum File Size" parameter. The spool disk > must be a fast one, especially if you want to run concurrent jobs. > Forget hdparm as benchmark, use bonnie++, tiobench, iozone. > > Then after after you have enabled spooling, restarted the SD, start > the backup. Look at the log file for "Despooling elapsed time". This > will show you how fast the spool file can be written to tape. > > The backup time will increase overall because the data will first be > written to disk and then to tape, but at least you eliminate the > network and the data source (server) as bottleneck. > > With spooling enabled and LTO-4 drives I get up 100 - 140 MB/s. > > Ralf >
Hi, thanks for your help. I think I was confusing some terms. The speed I reported was the total elapsed time that my backup took. But now according to your comments I got this from my logs: With spooling enabled: - Job write elapsed time: 102 MB/s average - Despooling elapsed time: 84 MB/s average Without spooling enabled: - Job write elapsed time: 68 MB/s average These are averages obtained from a group of 5 or more jobs of each case (with and without spooling). So I can see that with spooling enabled the process of writing to tape get higher speeds than copy-from-fd/write-to-tape without spooling enabled. Now the question is, why am I getting so low despooling speeds if I use LTO-5 tapes? Shouldn't I have higher speeds than you with LTO-4 tapes? I think the write speed of my tape it isn't the best. Some of my tests (all with spooling enabled) were done with "Buffer & Block size" settings at my storage daemon, but other tests were done without those settings, so I didn't see any appreciable enhancement of performance changing the value of block sizes. What can I do? ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
