On 09/25/2012 02:29 PM, Cejka Rudolf wrote: > Stephen Thompson wrote (2012/09/25): >> The tape in question have only been used once or twice. > > Do you mean just one or two drive loads and unloads? >
Yes, I mean the tapes have only been in a drive once or twice, possibly for a dozen sequential jobs while in the drive, but only in and out of the drive once or twice. I have seen this 200-300Gb capacity on new tapes as well as used. I see it in both my SL500 library as well as my C4 library, which is a combined 4 LTO3 drives (2 in each library). >> The library is a StorageTek whose SLConsole reports no media (or drive) >> errors, though I will look into those linux-based tools. > > There are several types of errors, recoverable and non-recoverable, and > I'm afraid that you see just non-recoverable, but it is too late to see > them. > >> Our Sun/Oracle service engineer claims that our drives do not require >> cleaning tapes. Does that sound legit? > > If you are interested, you can study > http://www.tarconis.com/documentos/LTO_Cleaning_wp.pdf ;o) > So in HP case, it is possible to agree. However, you still > have to have atleast one cleaning cartridge prepared ;o) > >> Our throughput is pretty reasonable for our hardware -- we do use disk >> staging and get something like 60Mb/s to tape. > > HP LTO-3 drive can slow down physical speed to 27 MB/s, IBM LTO-3 > to 40 MB/s. Native speed is 80 MB/s, bot all these speeds are after > compression. If you have 60 MB/s before compression and there are > some places with somewhat better compression than 2:1, then you are not > able to feed HP LTO-3. For IBM drive, it is suffucient to have places > with just 2:1 to need repositions. > >> Lastly, the tapes that get 200 vs 800 are from the same batch of tapes, >> same number of uses, and used by the same pair of SL500 drives. That's >> primarily why I wondered if it could be data dependent (or a bacula bug). > > And what about the reason to switch to the next tape? Do you have something > like this in your reports? > > 22-Sep 02:22 backup-sd JobId 74990: End of Volume "1" at 95:46412 on device > "drive0" (/dev/nsa0). Write of 65536 bytes got 0. > 22-Sep 02:22 backup-sd JobId 74990: Re-read of last block succeeded. > 22-Sep 02:22 backup-sd JobId 74990: End of medium on Volume "1" > Bytes=381,238,317,056 Blocks=5,817,238 at 22-Sep-2012 02:22. > Here's an example of a tape that had one job and only wrote ~278Gb to the tape: 10-Sep 10:08 sd-SL500 JobId 256773: Recycled volume "FB0095" on device "SL500-Drive-1" (/dev/SL500-Drive-1), all previous data lost. 10-Sep 10:08 sd-SL500 JobId 256773: New volume "FB0095" mounted on device "SL500-Drive-1" (/dev/SL500-Drive-1) at 10-Sep-2012 10:08. 10-Sep 13:02 sd-SL500 JobId 256773: End of Volume "FB0095" at 149:5906 on device "SL500-Drive-1" (/dev/SL500-Drive-1). Write of 262144 bytes got -1. 10-Sep 13:02 sd-SL500 JobId 256773: Re-read of last block succeeded. 10-Sep 13:02 sd-SL500 JobId 256773: End of medium on Volume "FB0095" Bytes=299,532,813,312 Blocks=1,142,627 at 10-Sep-2012 13:02. > Do not you use something from the following things in bacula configuration? > UseVolumeOnce > Maximum Volume Jobs > Maximum Volume Bytes > Volume Use Duration > ? > No, none of those are configured. Stephen -- Stephen Thompson Berkeley Seismological Laboratory step...@seismo.berkeley.edu 215 McCone Hall # 4760 404.538.7077 (phone) University of California, Berkeley 510.643.5811 (fax) Berkeley, CA 94720-4760 ------------------------------------------------------------------------------ How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
