Migration Planing
Server migration though seems daunting can be performed in a controlled, systematic fashion for most platforms. We have found that most people migrate to new systems due to security or performance related issues. If you have an aging server, you may have performance issues, security problems or both. Often if you lease, you will find it just as easy to migrate to a new server as to upgrade your old one.
Once you have decided to migrate your server, you should plan well in advance. At least a month is often warranted and perhaps longer if major changes are to occur. You need to work with your system administrator(s), developer(s), and clients to find a good time to migrate the sites. If you have a business-oriented clientele, then you can often schedule service over a weekend, thus minimizing the impact of any outages. You should plan on spending 2-5 days handling migration related issues. In addition to the server issues, you also must plan financially for all of the costs involved.
You will also want to make sure the new server supports your sites. This is often an issue if changing server control panels. For example, the Cobalt Raq's come with ASP built-in while Ensim and Plesk do not. Some servers may be using different mail programs that could cause issues with some scripts or mailing lists. All of these issues should be addressed before leasing/purchasing your new server.
Migration Costs
Migrating a server cost more than just the money you pay your sysadmin. You often need to carry the old and new servers for at least a month. Depending on your billing schedule and arrangements, you may not be able to cancel a server partway through a month and get a refund. We always advise handling migrations at the beginning of your billing cycle if you are paying monthly. This gives you plenty of time to work out any issues that may arise and gives you ample time to check for issues after migration. We've many cases where people do not discover a problem until a couple of weeks later; if you still do not have the old sever, files or configuration information may not be available.
Migration Procedures
We often divide server migration into six key areas:
- Pre-Migration Server Preparation
- Automatic/Scripted Migration
- Manual Migration
- Site Review
- DNS Changes
- Post Migration Issues
Pre-migration server preparations include any work required to get both the old and new servers ready for migration. This may include OS updates, control panel updates, some house cleaning or other tasks. We advise clients to clean out stale accounts before migrating. This reduces migration time and costs and assures your new server only has active sites.
Once the servers are prepped, we typically use scripted migration tools to move the sites, users, databases, email and other data between the servers. The extent to which the migration can be scripted is dependent on the type of migration. If you are changing control panels, then you will often find that scripted solutions only partially handle the migration. Some older systems may have to be migrated manually.
Manual migration can be quite costly and time-consuming. For large-scale manual migrations, you should hire a firm that specializes in this type of work. There are several companies that handle large-scale manual migrations. For many systems, you will find the migration tools to work reasonably well. You may have to manually migrate problematic sites, databases, special add-on software, or other items that are not explicitly covered by the migration software. Be sure to tell you sysadmin about any customizations you may have added to your server. Forgetting about these customizations could result in data loss during the migration process.
Once the sites are migrated, we suggest that you review them. Typically, HTML only sites migrate without issues and same control-panel migrations also have fewer issues. If you have changed control panels, then scripts and other dynamic content should be reviewed for errors. Paths often change when changing control panels, so some scripts may require adjustments. Also newer versions of software may introduce conflicts that need to be resolved. All of these issues are highly site specific. If you have a server full of complicated script powered sites, then expect more issues with a server with simple HTML sites.
If you made it through site review, you are almost done. The next step is to change DNS. The details of this are specific to each case. The key factors are if you control the name servers for sites. If you do, then often you simply just change records at your name servers. If not, then you must consult with your DNS provider on the best way to make these changes.
Once DNS changes are propagated, you may still find a few errors. For less busy sites, these may take weeks to pop up. Generally, they are only mild issues that can be quickly resolved. If you are hiring someone to handle migration, make sure they provide some level of post-migration support. They may not help with specific scripts but should be able to assist with sever level issues like extra Perl or PHP modules.
Migration Pitfalls
Common mistakes we see involve improper planning and insufficient time. We have often had clients approach us whom have already leased their new server and need the migration completed within 2-3 days. While this may work in some cases, most of the time it fails. The new server may not have the require specification, be ready to handle the sites, or not have a migration script. The number of sites and DNS changes may make it prohibitive to complete all of the changes in a short time frame. To avoid these issues, we recommend you plan migrations 30-60 days in advance.
Migration Services
rackAID provides migration services for major control panels. You will need to inquire about you specific case because we only handle scripted migrations for larger number of sites. Please be sure to include your current OS and control panel information as well as the number of sites. With this information, we can begin to work up an estimate for you.
