Moving SME to new Hardware
Introduction
There many ways to move a SME 7 Server installation to new hardware.
This document describes a method using the Affa contrib.
Affa makes it possible to move with a minimal downtime of the production server.
In the following it is assumed that prodIP is the IP address of your production server and newIP is the IP address of the new server hardware. Replace both placeholders by your real IP addresses.
Preparation
Production server
Enable remote ssh access in the server-manager of prodIP.
Log into the prodIP box and run an update
# yum update
If packages were updated signalling post-upgrade and reboot events is required.
New hardware
Install SME Server from the latest Cdrom/Iso. Assign an unused IP address (newIP) and disable DHCP.
Enable remote ssh access in the server-manager of newIP.
Note: From now on all further steps can be done remotely via ssh login.
Log into the newIP box and run an update
# yum update
Signalling post-upgrade and reboot events is required.
Download the smeserver-affa and perl-Filesys-DiskFree packages from one of the SME Server contrib mirrors.
Install both packges
# yum localinstall smeserver-affa*rpm perl-Filesys-DiskFree*rpm
Signalling post-upgrade und reboot events is not required.
Configure Affa
# db affa set prodserv job
# db affa setprop prodserv remoteHostName prodIP
# db affa setprop prodserv RPMCheck yes
Generate DSA keys and send the public key to the prodIP server
# affa --send-key prodserv
Copying data
Run the Affa job on the newIP box
# affa --run prodserv
Depending on the amount of data and the speed of hardware and network this first job run can take a really long time.
Now view the file /var/affa/prodserv/rpms-missing.txt
# less /var/affa/prodserv/rpms-missing.txt
You will find a list of RPMs which are installed on prodIP but not on this server (newIP) and also RPMs installed with different versions. Install or update the listed RPMs. To verify you can run the steps of this chapter again. Finally the rpms-missing.txt should not list any RPMs.
Final data synchronization
Ask your users to log off.
Log into the prodIP box and stop all services that can modify data.
# SVC='qpsmtpd sqpsmtpd crond imap pop3 imaps pop3s ftp httpd-e-smith atalk smb qmail'
# for s in $SVC; do service $s stop; done
Note: Downtime of the production server starts here
Log into the newIP box and run the Affa job again
# affa --run prodserv
This run will complete very quickly as only differences since the the last run needs to be synchronsized.
Switch over to the new hardware
Log into the prodIP box and power it off
# poweroff
Log into the newIP box and rise this server to your production server
# affa --rise prodserv
This action will complete very quickly as only hardlinks are used and no data is physically moved.
Now do a reboot
# reboot
Note: Downtime of the production server ends here
You now have an identical copy of your old production server running on the new hardware. Your users can now log on.
Cleaning up
Remove the Affa archives
# /bin/rm -rf /var/affa
Remove the Affa packages
# yum remove smeserver-affa perl-Filesys-DiskFree
Additional information
Performance
With this method you should be able to move a typical 50 Gbyte sized server to new hardware with downtime less than 20 minutes. The final sync and the rise time does not really depend on the total files size, but on the number of files and directories.
SME 6 Server
Although Affa was designed for SME 7, you can move a SME 6 server to a hardware with SME 7 installed. But there are few restrictions:
- You cannot yum update the SME 6
- You cannot use the RPM comparision, as SME 6 hasn't yum installed and all packages would differ anyway. Skip
db affa setprop prodserv RPMCheck yes - You must set rsync--inplace to no:
# db affa setprop prodserv rsync--inplace no
- The command
affa --rise prodservwill complain about old-style db pathes. Ignore these errors. After reboot login in as admin on the local console and set the new Network Interfaces manually. Reboot again. - You cannot work remotely.
