Bacula-users

Re: [Bacula-users] Speed of backups

2011-04-28 17:22:40
Subject: Re: [Bacula-users] Speed of backups
From: Ralf Gross <Ralf-Lists AT ralfgross DOT de>
To: bacula-users AT lists.sourceforge DOT net
Date: Thu, 28 Apr 2011 23:19:47 +0200
Jason Voorhees schrieb:
> 
> I think I was confusing some terms. The speed I reported was the total
> elapsed time that my backup took. But now according to your comments I
> got this from my logs:
> 
> With spooling enabled:
> 
> - Job write elapsed time: 102 MB/s average
> - Despooling elapsed time: 84 MB/s average
> 
> 
> Without spooling enabled:
> 
> - Job write elapsed time: 68 MB/s average
> 
> These are averages obtained from a group of 5 or more jobs of each
> case (with and without spooling). So I can see that with spooling
> enabled the process of writing to tape get higher speeds than
> copy-from-fd/write-to-tape without spooling enabled.
> 
> Now the question is, why am I getting so low despooling speeds if I
> use LTO-5 tapes? Shouldn't I have higher speeds than you with LTO-4
> tapes?
> ...

I got the biggest gain by changing "Maximum File Size" to 5 GB. How
fast is the disk where you spool file is locatet?

A different test would be to create a 10 GB file with data from
/dev/urandom in the spool directory and the write this file to tape
(eg. nst0). Note: this will overwrite your existing data on tape and
you might have to release the drive in bacula.

dd if=/spoolfile-directory/testfile of=/dev/nst0 bs=xxxk (your bacula block 
size)


Ralf

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