====== Run MYSQL with data files in memory ======

This is needed to protect the flash card if your application updates the data tables heavily.

1. Put [[backup-mydb.sh]] in ''/usr/local/bin''


2. Edit(set ROOTPW, ...etc) and **run the backup-mydb.sh script once**. 

3. Create mount point for new datadir, edit ''/etc/fstab'' , add lines:
<code>
# for mysql:
tmpfs           /var/mysqldata  tmpfs   defaults,size=16M       0 2
</code>

run:
<code>
mount /var/mysqldata
df -h
</code>

You see this line in the output:
<code>
tmpfs                  16M  1.2M   15M   8% /var/mysqldata
</code>

4. shutdown mysql, run:
<code>
invoke-rc.d mysql stop
</code>

5. Edit /etc/mysql/my.cnf, set
<code>
datadir         = /var/mysqldata
</code>

6. replace ''/etc/init.d/mysql'' with this [[mysql-init|modified version]].
(the modified one is based on 5.0.51a-24+lenny2)

7. start mysql, run
<code>
invoke-rc.d mysql start
</code>

The script will automatically restore all data files to ''/var/mysqldata''

You can also run ''backup-mydb.sh'' by cron periodically.

Next time when you normally shutdown the system, the data files is auto backed up.
When the system restart, the data files is auto restored.