If you had to configure a Wordpress MU installation without access to any details of your MySQL Configuration, what would you do?

What top five configuration settings would you use?

I asked the community this question, see For MySQL DBA fame and glory. Prize included and a number of brave soles responded for a chance to win a free copy of MySQL Administrators Bible by MySQL Community She-BA Sheeri Cabral.

There is no perfect answer and of course you would want to set more then five options, however the purpose of the competition was to seek what people would do with limited information and a limited choice of …

Update 8 June 2009
Be sure you to check out some of my research including Understanding your RAID Configuration and Understanding PERC RAID Controllers.

Last week I got caught thinking a MySQL production system wasn’t configured with RAID when it actually was. The following is the Linux dmesg output of 3 different client MySQL servers, where the H/W is all the same, a Dell 2950.

In the first two cases you will see individual references to the internal disks, however in the third you do not. This threw me, but as Matt Yonkovit correctly pointed out to me, the sizes are not standard drive sizes. …

Last week I posted the following twitter request — “Can somebody loan me (or buy me) a Dell 2950 decked out so I can run and publish some benchmarks. Please!”

In a same day response I was offered access to use 2 x Dell 1950’s, and today I’m now actually using these machines for my own testing. I would like to thank cafemom (Barry, Anthony & Dan) for the loan of hardware.

And now the chance to better understand the RAID configuration of the DELL PERC Controllers, trying out some different RAID types, LVM configurations and disk tests. When I’m done with my System Administrator refresher, I’m then be trying some different MySQL Benchmarks to test various MySQL configuration settings including using the new Juice …

I’ve decided to give people two more days for a chance to win a free MySQL Book — Sheeri Cabral’s MySQL Administrators Bible.

I have had five people so far provide recommendations for a simple MySQL configuration question as stated in For MySQL DBA fame and glory. Prize included. Shlomi Noach the current front runner.

Try your MySQL Performance Tuning skills. This is a good opportunity for new MySQL DBA’s and experienced DBA’s to provide basic input.

The reason for yesterday’s Basic OS/MySQL Security was a request to review a system and I was given the production server ‘root’ password in an email. Never email a ‘root’ password, especially including the hostname as well. Email is an insecure protocol that can be monitored by hackers. However, today’s basic security tip following a look at the system is:

Never store the MySQL ‘root’ user password in a ~root/.my.cnf file.

There is simply no reason to do so, and you expose your database to destruction or manipulation when a user has access to the ‘root’ OS user, for example via sudo.

I’ve heard excuses why the ‘root’ MySQL password has to be in a file, I’ve yet to be convinced.

Do you need to store a MySQL password in a file? Yes. Connection management for your application is an …

I came across the following configuration today on a Production MySQL system (5.0.67) running 30+ blogs using Wordpress MU.

$ cat /etc/my.cnf
[mysqld]
set-variable = max_connections=500
safe-show-database

No I did not truncate the output. I could say I’ve seen worse, but that’s a stretch.

So the quiz and a prize for the best response, for the next 48 hours I’ll accept your comments as responses to this post for the top 5 settings you would add, and additionally what information you may need to add these settings. Bonus points for giving a reason why you would add the settings as well.

For example, I’ll give you the most obvious.

key_buffer_size = ????

To determine a key_buffer_size to start with I would look at the size of all Indexes via I_S, and combine with some estimate of growth, say 2x-5x.

For the best answer …

If you can do either of these on your MySQL production server, you need to correct immediately.

1. Login directly to your MySQL server as the ‘root’ Linux Operating System user. For example:

$ ssh root@server-name
Password:  ************

2. Connect to MySQL database as the ‘root’ MySQL user without a password.

$ mysql -uroot

Here are the 60 second fixes to address these major security flaws.
To disable direct root access to your server, first ensure you can login as a normal user, then su - or sudo su - appropriately. Then, disable ssh root access with the following configuration change.

$   vi /etc/ssh/sshd_config
    # ensure this is commented out and set to no
    PermitRootLogin no

$   /etc/init.d/sshd restart

This will stop any brute force attack on your server by automated bots and password generators.

Second, the default installation …

I had the pleasure to sit on the Performance Panel at the recent Percona Performance Conference. While the panel contained a number of usual MySQL suspects, one person was not familiar, that being Cary Millsap from Method R.

An expert in optimizing Oracle performance, Cary also gave an session on Day 2 that I attended. While he opened professing not to be an expert in MySQL, his talk provided valuable foundation knowledge irrespective of whether you use MySQL or another database product.

Having come myself from 7 straight years in system architecture and performance tuning in Ingres, then a further 6 years in Oracle again heavily involved in system architecture and performance tuning, a lot of my …

Recently on a client site I had to fight the pain of having no way to confirm loss of data integrity when optimizing data types. Due to MySQL’s ability to perform silent conversion of data, when converting a number of columns we enabled sql_mode to catch any truncations as errors.

sql_mode=STRICT_ALL_TABLES

This ensured that should any data truncations occur, an error is thrown not a warning. The following shows an example case study for converting an INT to TINYINT UNSIGNED and shows that without sql_mode silent conversions occur.

mysql> drop schema if exists tmp;
Query OK, 25 rows affected (0.40 sec)

mysql> create schema tmp;
Query OK, 1 row affected (0.01 sec)

mysql> use tmp
Database changed
mysql> create table t1(i1 INT NULL);
Query OK, 0 rows affected (0.15 sec)

mysql> insert into t1 values(1),(2),(3),(256),(65536),(NULL);
Query OK, 6 rows affected (0.06 sec)
Records: 6  Duplicates: 0  Warnings: 0 …

As the recipient of the 2009 MySQL Community Member of the Year award I received a MySQL crystal ball. While it looks good in my bookcase, unfortunately the best advice I can offer during this time of uncertainty is “watch this space”.

A number of topics where information is still very much unknown and I’m either asked about, or am following includes:

• The Oracle acquisition of Sun, owner of MySQL.
• MySQL 5.4 Alpha release and schedule for production release
• The end of MySQL 5.0 Community/Enterprise split
• The future of Falcon in MySQL 6.0?

Thanks to Julian Cash of the Human Creativity Project of his photograph at the 2009 MySQL Conference.

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