When you run a manual backup in NetWorker (e.g., via the “save” command), NetWorker will by default give you a file-by-file listing of what is being backed up. In theory this is helpful for manual backups, because typically we do manual backups to debug issues, not as part of the production backup process.
If you’re wanting to do a manual backup and make it as high performance as possible, there’s an option you need to use: quiet. For the save command, it’s “-q”; for the GUI, it means going and bringing up a command prompt and learning how to use save*. You can’t turn off a file-by-file listing (currently at least) in the NetWorker user backup program.
So, backing up from a Solaris system to a Linux NetWorker server, using gigabit ethernet and the same backup device (ADV_FILE) each time, here’s some examples of the impact of viewing the per-file progress of the backup. (Each backup was run three times, with the run-time averaged.)
- Backing up 77,822 files:
- Without per-file listing: 53 minutes, 11 seconds.
- With per-file listing: 55 minutes, 35 seconds.
- Backing up 3,710,475 files:
- Without per-file listing: 1 hour, 38 minutes, 30 seconds.
- With per-file listing: 1 hour, 56 minutes, 9 seconds.
The time taken to print each file will be dependent on the performance of the console device you’re using. The above tests were run from an GigE ssh session from another host to the Sun client. (For instance, this problem also occurs in recoveries: I remember once running a recovery via a Sun serial console where I waited 6 hours for the recovery to complete only to discover when all the files stopped printing that the recovery had finished hours ago.)
The simple fact is – the more intensively you want to watch status of a backup (or for that matter, a recovery), the more you directly have an impact on its performance.
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* Honestly, you should anyway – see here for a good reason.