> dd test has been run... > > Just before the last run, I switched off the compression on the tape... > > > r...@backup:~# date; dd if=/dev/zero of=/dev/nst0 bs=1024k count=10240; date > Mon Jan 12 20:50:35 CET 2009 > 10240+0 records in > 10240+0 records out > 10737418240 bytes (11 GB) copied, 88.6869 s, 121 MB/s > Mon Jan 12 20:52:04 CET 2009 > r...@backup:~# date; dd if=/dev/zero of=/dev/nst0 bs=2048k count=10240; date > Mon Jan 12 20:56:32 CET 2009 > 10240+0 records in > 10240+0 records out > 21474836480 bytes (21 GB) copied, 170.224 s, 126 MB/s > Mon Jan 12 20:59:22 CET 2009 > r...@backup:~# mt -f /dev/nst0 rewind > ^[[ar...@backup:~# mt -f /dev/nst0 weof > r...@backup:~# date; dd if=/dev/zero of=/dev/nst0 bs=2048k count=82400; date > Mon Jan 12 22:48:58 CET 2009 > 82400+0 records in > 82400+0 records out > 172805324800 bytes (173 GB) copied, 1336.05 s, 129 MB/s > Mon Jan 12 23:11:14 CET 2009 > This is normal and the expected result.
> > # Switched off compression: > > mt -f /dev/nst0 compression off > > > r...@backup:~# date; dd if=/dev/zero of=/dev/nst0 bs=2048k count=102400; > date > Tue Jan 13 07:37:47 CET 2009 > dd: writing `/dev/nst0': No space left on device > 40406+0 records in > 40405+0 records out > 84735426560 bytes (85 GB) copied, 9176.92 s, 9.2 MB/s > Tue Jan 13 10:10:44 CET 2009 > r...@backup:~# > > > Just able to write 85 GB.... > This looks very much like either a bad tape or a bad tape drive or dirty heads on the drive. 9.2MB/s is way too slow and the time looks interesting. I mean this is the normal time to write an entire tape. Its like the drive is writing the entire tape but just at a very low density. I am no expert on how LTO writes to tapes but I do know that previous technology tape drives (DLT I believe) when it had media errors during writing it would rewrite the the block to the next position on the tape thus reducing capacity. I would perform a tape drive cleaning with a cleaning cartridge and perform the non compressed test again. If you get the same result try this with a brand new tape. John ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
