Hi Christopher, It sounds like you have other bottleneck issues elsewhere either with your disks or tape drive/cabling which could be slowing things down.
You might want to check for firmware updates for the tapes/disks/controllers. For LTO-4 your system needs to be able to sustain at least 200MB/s read speeds to feed your drive when using the drives onthefly compression regardless of what else is happening on the system.. for LTO-6 you would need and even faster i/o subsystem. The following bacula docs cover some troubleshooting. http://www.bacula.org/5.2.x-manuals/en/problems/problems/Testing_Your_Tape_Drive.html#SECTION00480000000000000000 From your config below.. I'm only using /dev/nst0. I'm not sure what features the device node your using does/doesn't support. On 11/30/2015 10:32 AM, Christoph Litauer wrote: > Andrew, > > many thanks for this hint. I installed the IBM driver and found the tape > drive testing tool itdt, too. > Now, using itdt and the new driver there is an improvement: > LTO6: 158 MB/s without compression, 177MB/s with compression > LTO4: 27 MB/s without compression, 128 MB/s with compression. > > For LTO6 this is in fact near to the theoretical limit (regarding random > data). > > Using btape with the new driver I still got 153MB/s (with compression) resp. > 39 MB/s (random data). > Seems as if there is a bottleneck in bacula? > My device configuration: > > Device { > Name = "LTO6-1" > Device Type = Tape; > Media Type = LTO6 > Archive Device = /dev/IBMtape0n > AutomaticMount = yes; > AlwaysOpen = yes; > RemovableMedia = yes; > RandomAccess = no; > Spool Directory = /var/spool/bacula > Maximum Spool Size = 300G > Maximum File Size = 5G > Maximum Block Size = 1m > } > > >> Am 28.11.2015 um 08:56 schrieb Andrew Ryder <tire...@shaw.ca>: >> >> 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 >>> > > -- > Freundliche Grüße > Christoph Litauer > _________________________________________ > Christoph Litauer > Uni Koblenz, Rechenzentrum, Raum A 022 > Postfach 201602, 56016 Koblenz > Fon: +49 261 287-1311, Fax: -100 1311 > > > > > > ------------------------------------------------------------------------------ > Go from Idea to Many App Stores Faster with Intel(R) XDK > Give your users amazing mobile app experiences with Intel(R) XDK. > Use one codebase in this all-in-one HTML5 development environment. > Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs. > http://pubads.g.doubleclick.net/gampad/clk?id=254741911&iu=/4140 > _______________________________________________ > Bacula-users mailing list > Bacula-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bacula-users > ------------------------------------------------------------------------------ Go from Idea to Many App Stores Faster with Intel(R) XDK Give your users amazing mobile app experiences with Intel(R) XDK. 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