There are a couple of ways it can be done, but the one I've chosen is to have a single 1TB external drive partitioned into two approximately 500GB partitions, putting the database on one and the web site on the other. You could just as easily use two drives. Actually it is easier, but it is more compact with a single drive, although one could argue that my 3.5 inch drive is not very compact.
Start with a full install of Raspian on an SD card.
Installing the software is the easiest part of this process. Do things in the order shown and it will just work. Then we'll do a little bit of customization.
sudo apt-get install apache2 sudo apt-get install mysql-server sudo apt-get install php5 sudo apt-get install php5-mysql
At this point, you can test the install by pointing your browser to "http://localhost/". You should get an html page showing the server is up. To test the PHP install, delete the html file and create a php file in the "/var/www/html" directory.
sudo su rm /var/www/html/index.html nano /var/www/html/index.php
Enter this one line:
<?php phpinfo(); ?>
Save the file and refresh your browser. You should get a page of configuration data for PHP. If so, the php installation worked. Copy the file to the user directory:
cp /var/www/html/index.php /home/pi
We need to unmount the external drive volumes. Rasbian automounts external drives. To find the volumes, use the following command:
mount |grep media
It will show all mounted volumes, similar to this:
/dev/sda2 on /media/pi/2bce3e4c-cac7-4336-9128-d5ed47191d95 type ext3 (rw,nosuid,nodev,relatime,data=ordered,uhelper=udisks2) /dev/sda1 on /media/pi/c8c7af08-dcbd-4d44-a7bb-8f4a8260d121 type ext3 (rw,nosuid,nodev,relatime,data=ordered,uhelper=udisks2)
Now we can unmount the volume(s).
umount /dev/sda1 umount /dev/sda2
The drive will need to be partitioned. It is necessary to delete any existing partitions before making new ones. The external drive on the Raspberry Pi is /dev/sda. We want to verify that using fdisk to get the USB device name. You should still be superuser (# prompt).
fdisk -l |grep "^Disk /" |grep -ve ram
That command yields these results on the Raspberry Pi 3B:
root@raspberrypi-web: # fdisk -l |grep "^Disk " Disk /dev/mmcblk0: 14.9 GiB, 15931539456 bytes, 31116288 sectors Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
We're only interested in that "/dev/sda" line. It might be "/dev/sdb" if there is another drive attached. Now we run fdisk on that specific drive.
If you want to familiarize yourself with fdisk commands, type
m for help. fdisk does not
write anything to the drive until you type the
w command. At that point, all changes are
written to the disk, and your drive configuration is changed. It is irreversible. The first thing to do is
delete any existing partitions. This is done with the
d command. It will prompt you for the partition
to delete. It defaults to the highest partition number. If that number is higher than one, there are
multiple partitions on the drive, and they will all have to be deleted. Use the
d command once for
After deleting the partitions, it is time to add new partitions. Two of them, each approximately half the
size of the disk. To do that, use the
n command. It will ask for the starting sector. Take the default.
Then it will ask for the ending sector. For a 1TB drive, enter
+500G and it will allocate 500GB to the
partition. If you are using an 80GB drive, then allocate
+40G to the first partition. When
you are back at the command prompt, enter the
n command again, and this time take all
of the defaults. It will allocate the rest of the disk to the second partition.
Until now, all commands have operated on an in-memory copy of the disk's partition table. Enter
w command and flush all changes to the drive.
Now you need to format the partitions. This is done with the ext2fs utility:
If it says the drive contains an existing filesystem, tell it to proceed anyway. This takes a few minutes on a 500GB partition. When it is done, do the other partition:
Again, it takes a few minutes. When it is done, you have two 500GB volumes that can be mounted wherever you want in the file system.
We will mount them to two different places in the filesystem. One will go to "/var/www" and will be for the Apache web server to use. The other will go to a new root directory called "/data" and will be for MySQL to use. First, you have to make a place in the filesystem to mount to. There is already a "/var/www". We know that because the web server worked. There is not a "/data", so we have to create that one. Still as the superuser (# prompt), type:
Now change the filesystem table "/etc/fstab" to mount our new volumes on the two mount points.
Your fstab should look like this:
proc /proc proc defaults 0 0 /dev/mmcblk0p1 /boot vfat defaults 0 2 /dev/mmcblk0p2 / ext4 defaults,noatime 0 1 # a swapfile is not a swap partition, no line here # use dphys-swapfile swap[on|off] for that
We're just going to add two lines at the end to put the new volumes where we want them:
/dev/sda1 /data ext3 defaults 1 2 /dev/sda2 /var/www ext3 defaults 1 2
Now, we can mount the volumes by running the mount command:
That command will attempt to mount all volumes in the fstab to their respective mount points. Proof that it worked will be that the web server no longer shows you the status page, but gives you a 404 error page. Refresh your browser and see if you get the error. You can also run the following command to get the volumes and mount points:
root@raspberrypi-web:/var/www/html# df -h Filesystem Size Used Avail Use% Mounted on /dev/root 15G 3.5G 11G 25% / devtmpfs 459M 0 459M 0% /dev tmpfs 463M 0 463M 0% /dev/shm tmpfs 463M 6.4M 457M 2% /run tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 463M 0 463M 0% /sys/fs/cgroup /dev/mmcblk0p1 63M 21M 43M 33% /boot /dev/sda2 425G 71M 403G 1% /var/www /dev/sda1 493G 100M 467G 1% /data tmpfs 93M 4.0K 93M 1% /run/user/1000
The database is currently writing data files to the /var/lib/mysql/mysql directory. We want to change it to write to /data/mysql. To do that, we have to edit the MySQL config file and copy the existing data to the new directory.
The area we are interested in looks like this:
[mysqld] # # * Basic Settings # user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp lc-messages-dir = /usr/share/mysql
The line we want is the "datadir" line. Change it to:
datadir = /data
That tells MySQL where to look, but it already built the files in /var/lib/mysql, so we have to copy the MySQL data to the new location:
cp -r /var/lib/mysql/* /data
And while we are copying:
mkdir /var/www/html cp /home/pi/index.php /var/www/html
One more thing. Permissions. The new volumes have either pi or root owners.
chown -R mysql:mysql /data chown -R www-data:www-data /var/www
Now for a final reboot. You should test the web server again to see that you get your php status page.