Colocation guide
Colocation Migration: A Technical Checklist
In short
Plan the move weeks ahead. Inventory every server and dependency, take a tested off-site backup, lower DNS TTLs, label every cable, check your rails and power connectors fit the new rack, then power on in dependency order: network, storage, hypervisors, databases, applications.
Moving physical servers is one of the riskiest jobs an IT team does: you unplug production, put it in a van and expect it to boot somewhere else. Most failures come from something nobody wrote down. This checklist runs in the order you'll need it.
Phase 1: Audit and document
Start weeks before anyone touches a power cable.
- Hardware inventory. Record every device's serial number, MAC addresses, warranty status, power draw and height in rack units (U).
- Dependency map. Write down what each server needs before it can start. If the database on one server must be up before the application on another boots, that sets your power-on order.
- IP addresses and firewall rules. Decide whether you keep your IP ranges or take new ones from the facility. List every NAT rule, VPN tunnel and firewall rule that names an address that will change.
- Backups. Take a full backup of every critical system, keep a copy off-site, and test that it restores. Hardware does get damaged in transit.
Phase 2: Plan the network cutover
- Lower DNS TTLs. 48 to 72 hours before the move, drop the TTL on affected records to 300 seconds, so changes to new IP addresses take effect in minutes. See pointing a domain to a new host.
- BGP, if you bring your own IPs. If you have your own IP space and ASN, agree BGP sessions with the new facility in advance so your announcements are ready to switch on.
- Pre-configure switches and firewalls. Set up uplinks and redundancy (LACP, VRRP) before move day, and test them as soon as the kit is racked.
- Out-of-band management. Configure IPMI, iDRAC or iLO for the new network. If the main network doesn't come up, it's your only way in.
Phase 3: Prepare the hardware and transport
- Label everything. Both ends of every power and network cable, and the front and back of every server with its hostname, target rack and U position.
- Check rails and power. Don't assume your rails fit the new racks: check rack depth and hole type (square or threaded). Check your PDUs match the facility's power connectors, such as C13 and C19.
- Pre-cable if you can. If you can get into the facility early, run switch cabling and power cords before the servers arrive.
- Move drives separately. For storage arrays, remove the drives, label them by bay and carry them in anti-static, padded cases. For heavy or valuable kit, use a specialist IT mover.
Phase 4: Rack, power on and test
- Rack to the plan. Follow your rack elevation diagram, with heavy kit such as UPS units and storage at the bottom and switches at the top.
- Separate power and data. Run power down one side of the rack and data cables down the other, and keep the airflow clear.
- Power on in dependency order. Core network first, then storage, hypervisors, infrastructure servers (DNS, directory), databases, and application servers last.
- Test before you sign off. Check out-of-band access, external connectivity and each application with its owner. Once everything is stable, put DNS TTLs back to normal.
Moving into our rack
With Gander Web colocation your server sits in our rack in a UK data centre, with power, network and remote hands for reboots, cable checks and drive swaps. Our uptime commitment is set out in our service level agreement. Talk to us before move day and we'll confirm rack space, power and IP addresses, so the checklist above has real numbers in it.
Moving servers into colocation?
Tell us what you're bringing and we'll confirm rack space, power and IP addresses before move day.
See colocationQuestions
How long does a colocation migration take?
Planning usually takes a few weeks. The physical move for a handful of servers can be done in a day. Most of the work is the audit beforehand and the testing afterwards.
Do I need to change my IP addresses?
Usually, unless you bring your own IP range and ASN. Plan for it: lower DNS TTLs and update firewall rules, VPNs and anything with an address written into its configuration.
What order should servers be powered on in?
Network first, then storage, hypervisors, infrastructure servers such as DNS and directory, databases, and application servers last.
What is remote hands?
Staff at the data centre who can reboot a server, check cabling or swap a drive when you can't be there.