In case we fail or accidentally destroy our HDD then we can get a new HDD and operating system from the datacentre and restore the data on a new drive. This concept can be used to migrate cPanel Servers from one server to another without loosing any data or creating any sort of downtime for websites hosted on the server.
This is how it will work:
1) Get the partitions from both the drives with:
# fdisk -l
2) Check to see if there are any drives mounted with:
# df -h
3) Let us assume that /dev/hdb3 is our CRASHED old drive and it is mounted as /mnt/old (yours can be different), but keep in mind that you need to know the mount point of the backup drive before we proceed further with the steps below.
Let us mount the CRASHED HDD if not already mounted with:
# mount /dev/hdb3 /oldHD
4) Now that the drive is mounted you can browse any files with:
# ls /oldHD/home
5) We are all set to move our data over to the new drive:
Run these rSync commands to move everything over:
rsync -vrplogDtH /oldHD/usr/local/apache/conf /usr/local/apache
rsync -vrplogDtH /oldHD/var/named /var
rsync -vrplogDtH /oldHD/home/* /home
rsync -vrplogDtH /oldHD/usr/local/cpanel /usr/local
rsync -vrplogDtH /oldHD/var/lib/mysql /var/lib
rsync -vrplogDtH /oldHD/var/cpanel /var
rsync -vrplogDtH /oldHD/usr/share/ssl /usr/share
rsync -vrplogDtH /oldHD/var/ssl /var
rsync -vrplogDtH /oldHD/usr/local/cpanel/3rdparty/mailman /usr/local/cpanel/3rdparty
rsync -vrplogDtH /oldHD/var/log/bandwidth /var/log
rsync -vrplogDtH /oldHD/usr/local/frontpage /usr/local
rsync -vrplogDtH /oldHD/var/spool/cron /var/spool
rsync -vrplogDtH /oldHD/root/.my.cnf /root
rsync -vrplogDtH /oldHD/etc/httpd/conf/httpd.conf /etc/httpd/conf
cd to the old etc directory:
And copy some files from here:
#rsync -vrplogDtH secondarymx domainalias valiases vfilters exim* proftpd* pure-ftpd* passwd* group* *domain* *named* wwwacct.conf cpupdate.conf quota.conf shadow* *rndc* ips* ipaddrpool* ssl hosts /etc
6) We are done with the copying of all the files and cPanel should start recognizing all the old users and their files, but after we do all this it is highly suggested that you run all updates, and run the cPanel fix scripts i.e:
Updating software and restarting services:
7)This is needed to update cpanel information. Please note, sshd might fail and not start after running fix everything. You have to login to whm, and go to the rpm installer and “FORCE” install opensshd-server, opensshd, opensshd-client and then restart sshd from whm.
Restarting services as:
That is all we need to recover data from a CRASHED HDD.
Procedure to Migrate live cPanel Server to a new cpanel server
Same procedure can be used to migrate one server to another without any data loss or downtime. The following steps will be different in this case and for this particular requirement you will need to go through the following configurations :-
1) Share SSH keys between both servers (only if you have full control of both servers). To share SSH keys you will first need to generate keys on both servers with following command :-
#ssh-keygen -t rsa -b 1024
Run above command only if you dont have any information in ‘/root/.ssh/ directory’. Once the keys are generated you will see the following files in the directory :-
id_rsa id_rsa.pub known_hosts
Now to share the keys you need to copy the contents of id_rsa.pub file and create a new file called authorized_keys in the same directory on the other server. Paste the contents of id_rsa.pub of server1 in server2 and server2 in server1 authorized_keys. Sharing SSH keys in this way will allow you to sync data between both servers without any sort of password authentication. You will need to create this file (authorized_keys) as it won’t be there by default.
Browse to the ‘/etc’ directory on the source server and run following command from that directory :-
#rsync -vrplogDtH secondarymx domainalias valiases vfilters exim* proftpd* pure-ftpd* passwd* group* *domain* *named* wwwacct.conf cpupdate.conf quota.conf shadow* *rndc* ips* ipaddrpool* ssl hosts email@example.com:/etc
(10.10.10.2 is assumed as the IP of the new server to which we are moving the data.)
Now we need to transfer everything else.
rsync -vrplogDtH /usr/local/apache/conf firstname.lastname@example.org:/usr/local/apache
rsync -vrplogDtH /var/named email@example.com:/var
rsync -vrplogDtH /home/* firstname.lastname@example.org:/home
rsync -vrplogDtH /usr/local/cpanel email@example.com:/usr/local
rsync -vrplogDtH /var/lib/mysql firstname.lastname@example.org:/var/lib
rsync -vrplogDtH /var/cpanel email@example.com:/var
rsync -vrplogDtH /usr/share/ssl firstname.lastname@example.org:/usr/share
rsync -vrplogDtH /var/ssl email@example.com:/var
rsync -vrplogDtH /usr/local/cpanel/3rdparty/mailman firstname.lastname@example.org:/usr/local/cpanel/3rdparty
rsync -vrplogDtH /var/log/bandwidth email@example.com:/var/log
rsync -vrplogDtH /usr/local/frontpage firstname.lastname@example.org:/usr/local
rsync -vrplogDtH /var/spool/cron email@example.com:/var/spool
rsync -vrplogDtH /root/.my.cnf firstname.lastname@example.org:/root
rsync -vrplogDtH /etc/httpd/conf/httpd.conf email@example.com:/etc/httpd/conf
One more thing which needs to be done in this case is a mass replace command for changing the IP address in the zone files and httpd.conf. Here’s a command to help you do it in a few seconds :-
replace 10.10.10.1 10.10.10.2 — /var/named/*.db
replace 10.10.10.1 10.10.10.2 — /usr/local/apache/conf/httpd.conf
10.10.10.1 is assumed as the IP of source server.
10.10.10.2 is assumed as the IP of the new destination server which will now run your websites.
If you run this mass replace command on the source server as well then all the websites will start pointing to the new server immediately which will ensure no downtime for your websites. This concept can be used for a Cheap VPS Hosting as well.