[CentOS] upgrading Mysql 5.0.95

Sun Mar 19 12:32:38 UTC 2017
Mark Weaver <mweaver at compinfosystems.com>

Hi All,

I'm getting things ready to upgrade my aging installation of MySQL
5.0.95 on my CentOS 5 LAMP server. With the impending EOL date of 3.31
fast approaching my sense of doom and urgency is increasing.

I see that the necessary packages are available in @base and @updates -
mysql51 and mysql55 respectively but from all the information I've read
on the matter so far I'm left with a few questions I don't yet have
answers to.'

What I've done so far and thankfully was able recover from:

1. installed and enabled to epel repo
    - ran yum remove mysql
    - this command wanted to remove a few things I wanted to keep in
      place like dovecot and a few php53 packages. I didn't want to have
      to go back and clean up any messes that would create. So, I used
      the rpm -e --nodeps command to remove the MySQL packages.
    - because this was a redhat repo it installed the binaries in a
      total different place AND tossed all my existing data directories.
      and yes I spit coffee all over my laptop screen and yes, I did have
      data dir backups and a dump of MySQL data. HOLY CRAP!

2. removed the epel packages
   - disabled this repo - for ever at least for now...

3. reinstalled the old MySQL 5.0.95 packages - because I was
   - reset roots password
   - imported all the databases from the dump and checked my web apps
   - everything working again.
   - I did have to recreate the mysql.servers table to be able to flush

I understand that mysql51 is available in @base for the sole purpose of
upgrading old MySQL and mysql55 is in updates for getting to 5.5,
however here is where things get a little fuzzy for me:

Steps for Upgrading (as I understand them):

1. Take a dump of all mysql database using mysqldump --add-drop-database
2. Stop mysql services
3. make a backup of data directories: /var/lib/mysql (but its not 
_supposed_ to remove the data directories.)
3. yum remove mysql mysql-server (again, it will include a few things I 
don't want removed. so, i'll have to use rpm -e --nodeps and list the 
packages for removal then issue yum clean all.'
4. yum install mysql51
5. start mysql service
6. run command mysql_upgrade...
(here's where things start getting fuzzy)

Question #1:
   is this command to be run from the commandline or	
   should I log into mysql as root user and run the command?

Question #2:
   at this point I will have mysql 5.1 installed and running but to get
   up to 5.5 am I expected to yum remove 5.1 and then yum install 5.5
   from @updates and repeat steps 5 and 6 OR simply run the command
   yum update mysql51* to catch all already installed mysql51 packages
   to and then run the mysql_update command to bring data up to date
   with the current mysql install?

THank you for your kind attention...