Callmanager Migration Thoughts

Here are some thoughts about migrating to a new Callmanager version. Should you have any remarks or addition to these points please post them in the comments.

Backups, backups, backups

Backups provide a really good starting point for your migration. They really do. There are different ways to accomplish this:

• You can pull a hard disk from the RAID set on any (or all :-) ) of the running machines. If you pull a disk, you might want to consider replacing the disk rather than just pulling it. Remember to check for the right disk size (you need at least the same capacity, so 72GB for a pulled disk of 36GB is fine) and preferably the same RPM count (if you replace a 15K disk with a 10K disk, the set will run at 10K: the lowest disk dictates the speed of the set).
• You can create a backup through the BARS or serviceability interface.

Oh, and about replacing that pulled disk rather than just pulling it: I’ve heard about situations where that single disk decided to fail in the little timespan it had to work on its own.

Consider yourself warned, you might find yourself in a situation where you’re empty handed and have no-one to blame except yourself.

Communicating towards your end users

Perhaps the most important bit about migrating from one CCM version to another. Talk to your end users. Let them know what’s happening.

• What is going to change?
• What remains the same?
• What is the planned outage of your environment?
• Who can be contacted (on which phone number) in case of any problems?

Software

• Collect all the PC software from you old and new CCM version. In a large environment, you might consider scripting the various pieces of software, like the Attendant Console, Assistant Console, etc.
• Collect all the phone loads you intend to use. Don’t forget ATA’s and conference phones like the 7936.
• Consider upgrading your phones beforehand, so you don’t have to wait for the phones to come back after the upgrade when you are migrating your CCM environment. If you choose to do this, make sure that your old CCM version has no issues with the new phone load(s).
• Make sure the IOS versions of your switches and routers are compliant with the CCM version you’re migrating to.

So you read through all this? Good for you. Now read that section about backups again.

Partitions and Calling Search Spaces

• Do your new calling search spaces contain the right partitions?
• Are the partitions in your calling search spaces prioritized right?

Using BAT (Bulk Administration)

• Import your phones and users (and all other data like pickupgroups if applicable), and check whether everything is imported as desired. Not really a ‘dry run’, but validating the BAT templates just isn’t cutting it.
• Specifically, pay attention to call forward destination columns and call forward calling search spaces.

Speeddials and Personal Address Book

• The Speeddials in applications like the Assistant and Attendant console can’t be export if you’re using the CCM 4.x version. The ones in the assistant Console can’t be exported or duplicated. You need to copy them by hand. The ones in the Attendant Console are automatically saved when the network connection is lost. If you have more than one location (for example, multiple branch offices), you could log in to the same (local) pc with the software installed, pull the plug on the network interface and save the local stored file. You can copy this file to the pc with the upgraded software and use it.
• The Speeddials and Personal Address Book can be exported from within the DC Directory Administrator (note: still to provide an example DN)

Licensing

• If you’re migrating to CCM6, be aware of the new licensing structure; be sure to calculate the right amount of license units needed.
• Disable any functionality which you don’t really need (like Mobility (not to be confused with Extension Mobility).

Other issues

• Consider decreasing the DHCP lease time for your voice VLAN(s). The best way to this is by gradually decreasing the lease time. Should your DHCP server fail while preparing for the CCM migration, the department responsible for the DHCP server has the maximum amount of time to fix it. For example, if the voice VLAN leasetime is 10 days, you set it to be 5 days on day 11 before the CCM migration date. On the 6th day before the CCM migration date, you set the leasetime to 2 days. On the 3th day for the migration date, you set it to one day, etc. You can also use this strategy when increasing the leasetime after the upgrade.