topic Re: Fbackup in verbose mode vs. performance in Operating System - HP-UX

Fbackup in verbose mode vs. performance

Mihails Nikitins — Wed, 13 Sep 2000 15:31:05 GMT

Hello,

I noticed that fbackup in verbose mode runs very slow. It seems to me that the backup process waits for file name to be written on the console and then writes the next file. Performance degrades dramatically, especially writing a large number of small files. Do I understand the problem correctly?

My solution would be not to use "-v" option, using "-I" instead. I.e.

a bad idea is
fbackup -f /dev/rmt/0m -0vi /

A faster solution could be
fbackup -0i / -I indices/all -f /dev/rmt/0m

Thank you for any comments about good fbackup practices.

Re: Fbackup in verbose mode vs. performance

Stefan Farrelly — Wed, 13 Sep 2000 15:33:50 GMT

If you use verbose mode and redirect the fbackup output to a file its just as quick as not having verbose mode. We use it all the time.
ie. fbackup ....... >/tmp/daily_backup.out 2>&1

Re: Fbackup in verbose mode vs. performance

John Palmer — Wed, 13 Sep 2000 15:38:49 GMT

To get the best performance out of fbackup you need to tune it by providing various parameters in a 'config' file. Probably the most important one being 'blocksperrecord' which defines the tape blocksize used.

There have been a number of threads in this forum recently that give more information. I suggest that you use the SEARCH facility anc check FORUMS looking for fbackup.

Re: Fbackup in verbose mode vs. performance

Mihails Nikitins — Thu, 14 Sep 2000 07:58:20 GMT

Thank you, output redirection will solve the problem!

Re: Fbackup in verbose mode vs. performance

Alan Edwards — Thu, 14 Sep 2000 20:31:03 GMT

I would go with the -I index option. The problem with redirecting all std and error output to a file is that you cannot respond to errors such as a write protected tape.

I recently had to update a backup script because of just this problem. The fix I made used the -g graph, -V vol_head, and -I index options for a complete record trail.

Re: Fbackup in verbose mode vs. performance

Mihails Nikitins — Fri, 15 Sep 2000 07:07:34 GMT

On one hand, it is a good idea to catch all error messages in a file. On the other hand,
we may need stderr on the console (e.g., to replace media if it is full).

Is it possible to send stderr to both file and console?

Re: Fbackup in verbose mode vs. performance

Kofi ARTHIABAH — Fri, 15 Sep 2000 07:39:53 GMT

Yes you can use the tee command. do a man on tee

Here is what you might want to try..
fbackup ....... 2>&1 | tee -a /tmp/daily_backup.out

Re: Fbackup in verbose mode vs. performance

Mihails Nikitins — Fri, 15 Sep 2000 07:58:15 GMT

> fbackup ....... 2>&1 | tee -a /tmp/daily_backup.out
This construction will send all output to console. If I need to see everything in a log file and errors on console, probably, I cannot not use "-v" option, I may use "-I" instead.

I do not see possibility to get the same result with "tee" and output redirection (stderr to both console and file, stdout to file only).

Re: Fbackup in verbose mode vs. performance

Kofi ARTHIABAH — Fri, 15 Sep 2000 08:19:18 GMT

Sorry about that I now understand what you wanted... you can achive that with tee by sub-command executionn like:

(fbackup .... 1>/tmp/output1) 2>&1 | tee -a /tmp/backup.out

this will execute the construct in bracket as one unit, and then any errors generated are sent to a new file descriptor 1 which is then tee'd to your file.

Re: Fbackup in verbose mode vs. performance

Mihails Nikitins — Fri, 15 Sep 2000 08:47:19 GMT

Thank you, it is exactly what I wanted. :-)