Bacula-users

Re: [Bacula-users] Database performance issues

2011-06-08 12:54:13
Subject: Re: [Bacula-users] Database performance issues
From: Phil Stracchino <alaric AT metrocast DOT net>
To: bacula-users AT lists.sourceforge DOT net
Date: Wed, 08 Jun 2011 12:51:07 -0400
On 06/08/11 11:44, Jérôme Blion wrote:
> On Wed, 08 Jun 2011 10:50:58 -0400, Phil Stracchino <alaric AT metrocast DOT 
> net>
> wrote:
>> The very first thing I would do would be upgrade to MySQL 5.5.[current]
>> (5.5.13, right now) if you're not already using 5.5, making sure it's
>> properly configured (hint:  look at the new configuration directive
>> innodb_buffer_pool_instances), then throw as much RAM as possible at the
>> InnoDB buffer pool and convert all of the tables to InnoDB.  Then
>> download MySQltuner (http://mysqltuner.com/mysqltuner.pl) and look at
>> its recommendations for some basic tuning.
> 
> InnoDB is not so easy to setup. The biggest buffer is not always the best
> one.
> 
> innodb_buffer_size should be bigger than innodb data pieces.
> You should seize logfiles according to the database activity.
> You should set innodb_file_per_table... and so on...

Well, obviously, yes.  I wasn't trying to give a complete MySQL tuning
guide in a single message.  I will note' however, that benchmarking has
demonstrated that InnoDB performance scales more or less linearly with
InnoDB buffer pool size up to about 300GB.

> When we are speaking about Mysql performance, you could have a look on
> InnoDB plugin.
> Barracuda file format is much faster than the previous one, the innodb
> plugin is known to improve performance.

This is outdated information dating from MySQL 5.1.  In MySQL 5.5 there
is only one InnoDB storage engine, and it is a newer, more advanced, and
better-performing engine than the MySQL 5.1 InnoDB plugin.

> SELECT are slower on a InnoDB table. (but is much more reliable)
> When the database has a really slow update frequency, MyISAM can be
> interesting.

Actually, this is one of the misconceptions.  I actually had cause
recently to do some benchmarking of MySQL on top of several different
underlying storage options.  One of the things that did come out of the
test is that, on MySQL 5.5 at least, even in a 100% read workload -
which is the best possible performance case for MyISAM - InnoDB still
consistently outperformed MyISAM by approximately 60%.  (For the record,
in a 25% write/75% read workload on the same configuration, InnoDB
outperformed MyISAM by 400%.)


-- 
  Phil Stracchino, CDK#2     DoD#299792458     ICBM: 43.5607, -71.355
  alaric AT caerllewys DOT net   alaric AT metrocast DOT net   phil AT 
co.ordinate DOT org
  Renaissance Man, Unix ronin, Perl hacker, SQL wrangler, Free Stater
                 It's not the years, it's the mileage.

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