Are you using the IBM Linux tape driver? If not, I'd suggest installing it vs the generic linux kernel's tape driver.
http://www-933.ibm.com/support/fixcentral/swg/selectFixes?parent=Tape%2Bdrivers%2Band%2Bsoftware&product=ibm/Storage_Tape/Tape+device+drivers&release=1.0&platform=Linux&function=all On 11/27/2015 08:43 AM, Christoph Litauer wrote: > Dear bacula users, > > I recently recognized that my tape drives do not perform as expected. Neither > while used with bacula nor native with dd. I did many performance tests in > the meantime but could not figure out the reason. So may I ask in this group > what typical write speeds you have with your tape drives? > > I tested LTO6 (IBM Ultrium HH6) and LTO4 (Ultrium 4-SCSI). Both are part of > two libraries connected via SAS to a LSI SAS3801E-controller. The host system > runs SLES12. > I used btape and dd for writing. > I figured out the best writing performance with blocksize 512KB (LTO4) resp. > 2MB (LTO6). Both drives with compression on. > > LTO4 best performance (writing zeros): 115 MB/s > LTO4 worst performance (random data): 71.58 MB/s > > LTO6 best performance (zeros): 153 MB/s > LTO6 worst performance (random): 58 MB/s > > Disabling compression does not change the maximum speed. In this case writing > zeros is the same as writing random date (expected). > > According to Wikipedia, theoretical speed should be > LTO4: 240 resp. 120MB/s > LTO6: 400 resp. 160MB/s > > Any ideas welcome! Thanks in advance! > > -- > Kind regards > Christoph > _________________________________________ > Christoph Litauer > Uni Koblenz, Computing Centre, Office A 022 > Postfach 201602, 56016 Koblenz > Fon: +49 261 287-1311, Fax: -100 1311 > > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Bacula-users mailing list > Bacula-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bacula-users > ------------------------------------------------------------------------------ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
