Summary
While verifying tape-based backups on UNIX systems, the job log may report Input/Output errors even though a job has completed successfully. This problem pertains only to UNIX based operating systems, such as AIX and Linux, and occurs when the operating system signals an End Of Tape condition during the verification of partitions at the end of a tape.
Symptoms
The following job log section illustrates the typical messages reported when a Tape Change condition occurs during the backup phase of a job:
10.1.3.121 ssjobhnd Sun Nov 25 00:21:35 2007 SNBJH_3257J ----- Task 9 (node B, disk USR:) of job 1195974000 starts -----
10.1.3.75 ssdmtape Sun Nov 25 00:21:42 2007 SNBDBR0494I dm_get_keyword: Possible EOF on socket 6.
10.1.3.75 ssdmtape Sun Nov 25 00:29:41 2007 SNBTIO1024E Error writing to file <NULL>, rc=-1
10.1.3.75 ssdmtape Sun Nov 25 00:29:41 2007 SNBTIO0028S No space left on device
10.1.3.75 ssdmtape Sun Nov 25 00:29:41 2007 SNBDBR0540I dm_write_tape: RC (-1) from tio_writetape.
10.1.3.75 ssdmtape Sun Nov 25 00:29:41 2007 SNBDBR0701W dm_process_send_backup_data_enh: Encountered Logical End Of Tape.
This subsequent job log section illustrates the Input/Output error reported on the same partition when an End of Tape condition occurs during the verification phase of a job:
10.1.3.121 ssjobhnd Sun Nov 25 00:29:40 2007 SNBJH_3468J --- Starting verify for device LTO in job 1195974000 ---
10.1.3.75 sstptmm Sun Nov 25 00:30:35 2007 SNBTMM5471I Node(h) drive(LTO) volser(000000) partition(2) position rc=(0)
10.1.3.75 ssdmtape Sun Nov 25 00:41:58 2007 SNBTIO1025E Error reading from file <NULL>, rc=-1
10.1.3.75 ssdmtape Sun Nov 25 00:41:58 2007 SNBTIO0005S Input/output error
10.1.3.75 ssdmtape Sun Nov 25 00:41:58 2007 SNBDBR0540I dm_read_tape: RC (-1) from tio_readtape.
10.1.3.75 ssevthnd Sun Nov 25 00:41:58 2007 SNBEHT4380W <<< End of tape encountered during verify of tape 000000 on drive LTO >>>
10.1.3.121 ssjobhnd Sun Nov 25 00:41:56 2007 SNBJH_3469J --- Finished verify for device LTO in job 1195974000 ---
Resolution
Considering the backup job, including the verification phase, completes successfully when the above Input/Output error is reported, this incorrect error message can simply be ignored.