[LON-CAPA-admin] Upgrading server hardware

[Stuart Raeburn]

Lars,

>
> ...What is the deal with the mysql/mariadb admin password. Is it ever needed?
>

You should set the mysql/mariadb admin password to something secure,  
but there is no reason to actually use it in normal operation of  
LON-CAPA, because LON-CAPA uses a different (less privileged)  
mysql/mariadb account when access in needed to the loncapa database in  
MySQL.

The only reason you might use the admin password would be if you  
wanted to add your own MySQL user accounts and/or databases to your  
LON-CAPA instance, but that is not something I expect you would ever  
need to do.

> And apparently it wasn't needed for loncapa to gain access the
> database once it was copied over to the new server, because everything
> on the new system seems normal.

Correct. When you run the ./install.pl script if you answer Y for both  
of the options: "Set-up the MySQL database?" and "Set-up MySQL  
permissions?" then the appropriate user account and permissions are  
set up for LON-CAPA to use MySQL.

Currently LON-CAPA only stores data temporarily in MySQL tables, and  
all the authoritative (permanent) data are stored in GDBM .db files on  
the filesystem. The MySQL tables are used for short-term caching of  
data, and to speed up certain types of queries.

The MySQL LON-CAPA data are actually stored in /var/lib/mysql/loncapa  
which is not included amongst those directories identified for copying  
in the advertised procedure used to upgrade the hardware or OS for a  
LON-CAPA server. The reason is that those tables will be populated,  
either by entries in /etc/cron.d/loncapa run by cron, or by actions in  
LON-CAPA itself (e.g., displaying grades or generating reports).

For example, see a previous post of mine to this list:
http://mail.lon-capa.org/pipermail/lon-capa-admin/2016-January/003175.html


Stuart Raeburn
LON-CAPA Academic Consortium

Quoting Lars <ljensen at tmcc.edu>:

> Thanks Stuart. You were right on the money. All I had to do was to
> install the perl-LDAP module, and everything started right up. What is
> the deal with the mysql/mariadb admin password. Is it ever needed? I
> have forgotten it and I don't remember ever using it on my old server.
> And apparently it wasn't needed for loncapa to gain access the
> database once it was copied over to the new server, because everything
> on the new system seems normal.
>
> Lars.