We see more IT departments considering NPM/APM adoption when dealing with data center moves, mergers and consolidations.
These migrations may be driven by mergers, group data center consolidation or simply migrating to a hosting center or a private cloud. Some of them may look at this technology a little late (to help them fix degradations / misconfigurations which appeared during the migration), but many of them take the best practice and leverage the capabilities of NPM and APM solutions to assess the current performance, prepare, plan, execute and review their migration.
Such a migration takes time and means there will be an intermediary stage between the start and the end of the migration which can last a certain number of weeks and months; during that period one part of the systems will be in the initial data center and another one will be in the target data center. Managing the performance rendered to the end users during that period is a challenge.
This article is a short description of the main stages at which a performance management will help you mitigate the risks attached to major infrastructure changes.
Before the migration
1. Measure the end user performance in the initial situation
2. Collect the performance data to figure out how you migrate your systems
To establish the best plan (what to move, in which order) and avoid future errors, downtimes and performance degradations during the migration you need to collect the following data and make sure it is accurate:
- Establish a list of all the critical application chains
- Dependency mapping: understand the dependency between the different hosts (infrastructure services like DNS, Storage, authentication servers, and all the hosts of the different tiers of each application, identifying which IP addressing may also be hard coded)
- Understand the network requirements between all these hosts (volume and bandwidth) and the performance profile of each type of communication (respective impact of network, server processing and data transfers on the end user response times)
3. Anticipate the added latency during the migration and the impact on the end user experience
When considering a significant size move / migration, you will certainly have to phase this operations in various steps or waves. This will drive you to a situation where some of the systems are in your original datacenter and some are already migrated.
Obviously both host groups will keep communicating and exchanging data through a larger distance and network latency. This will have an impact on the end user response times. You need to anticipate how much this impact will be for the end users. As an example, If this stage adds an additional 10ms of network latency, depending on what drives the average server processing time and the quantity of data which is exchanged, it may drive to acceptable, non-acceptable response times or an outage for time-sensitive applications.
Execute the migration
4. Keep performance under control during the move / migration
During the migration, performance slowdowns, incidents and other complaints will be reported to your helpdesk; they may be more numerous that during a normal period; they may target existing problems as well as new issues.
The migration operation will certainly be the #1 suspect!
You need to be well prepared and continuously monitor end-to-end response times and errors on the legacy and the target data centers to avoid:
- any performance degradations resulting in business losses (productivity and / or revenue)
- any delay in the execution of the migration
- any lack of shared performance data driving to a lack of collaboration (between IT departments – network, system, database, applications) when troubleshooting slowdown issues
- finally any negative feedback on your team’s work
After the migration
5. Analyze and identify remaining errors / misconfigurations
Migrating large IT systems comes with a massive amount of complexity; whatever the level of preparation and resources you had, some items will be missed and may remain invisible.
You have to conduct a review of all patterns corresponding to misconfigurations or inherited behaviors (hosts calling non existing services, hosts and network segments; one-way communications and data flows to old addressing plans should also be tracked).
6. Measure and report on the end-to-end user performance after the migration
Once the migration is considered completed, you should measure the end user performance and report the variation (if possible improvement) which comes with the implementation of the new infrastructure.
Don’t forget to request a promotion for the good job you’ve done!