000-221 · Question #17
The system administrator ran the following command to backup his image repository, but nothing was backed up to the file. Why? find /media -print | backup -I-f-p /dev/rmt0
The correct answer is B. The files in the directory are larger than 2GB. The AIX backup command cannot handle individual files larger than 2GB when reading filenames from stdin via the -i flag, causing those files to be silently skipped.
Question
The system administrator ran the following command to backup his image repository, but nothing was backed up to the file. Why? find /media -print | backup -I-f-p /dev/rmt0
Options
- AThe block size was not specified.
- BThe files in the directory are larger than 2GB.
- CThe tape was not positioned the beginning of the tape.
- DThe tape was not formatted.
How the community answered
(43 responses)- A2% (1)
- B79% (34)
- C14% (6)
- D5% (2)
Why each option
The AIX backup command cannot handle individual files larger than 2GB when reading filenames from stdin via the -i flag, causing those files to be silently skipped.
The backup command does not require an explicit block size argument for tape operations; a default block size is used automatically.
The AIX backup command has a 2GB per-file size limitation due to 32-bit offset constraints in its archive format when operating in file-mode (reading filenames from stdin with -i). Files exceeding this limit are not backed up and no error is reported, resulting in the observed behavior of nothing being written to tape even though the command appeared to run.
Tape positioning affects where data is written on the tape but would not cause the backup to produce no output at all - it would write data at the current position.
The AIX backup command writes its own tape format and does not require the tape to be pre-formatted before use.
Concept tested: AIX backup command 2GB file size limitation
Source: https://www.ibm.com/docs/en/aix/7.3?topic=b-backup-command
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