Three Steps to De-Risking Migration to the Private Cloud

Best Practices, Private Cloud, virtualization No Comments »

One of our customers recently completed a major datacenter consolidation, which included a move to a private cloud infrastructure for some of their applications.  I asked them how the private cloud initiative went and what they think they’ll get out of it.  During the discussion, they mentioned that they used VirtualWisdom to help with the migration, including the deployment of a major app on vSphere.  I thought I’d share the 3 discrete migration-best-practice steps they took, using VirtualWisdom, to ensure that the project went well.

1.     Find and Eliminate Connectivity Errors

This meant cleaning up multi-pathing errors, both in terms of single paths and of unbalanced paths.  To no one’s surprise, they found quite a few areas that needed clean-up.  At the same time, they monitored for physical layer issues, found one serious bottleneck they uncovered by looking at buffer to buffer credits, and remediated it.  Their private cloud migration uses virtualization at both the server and storage level, with a greater utilization of all components, so finding and fixing physical layer issues before the move was deemed essential.

2.     Ensure Optimal Performance

Because part of the project was a consolidation effort, the customer needed to review the configuration of their storage network.  Finding problems and opportunities for reducing the physical number of links without impacting performance was key.  They reviewed Queue Depth settings and found hidden performance improvements that gave them extra bandwidth head-room on the most-used links.

The customer used Exchange Completion Time, the measure of an I/O from the initiator to the LUN and back, as the key metric for performance testing.  They benchmarked application latency before the queue depth settings were changed, and after, and were able to prove the positive impact.  Then, as they brought applications over, they were able to instantly determine, to the millisecond, the impact of the migration on application latency.  This prevented potential user satisfaction issues, and they were able to prove that the consolidation project and separately, the private cloud migration did not hurt application response times.

3.     Optimize Utilization, Reduce Congestion

Good network capacity planning can help maintain networks in optimal working order.  It can reduce the risk of outages due to resource limitations, and justify future networking needs.  It’s important to look for patterns that occur at various times of day. There are often the equivalent of “rush hour” time periods where the SAN traffic will be slowed due to periods of significantly increased demands.   Using the VirtualWisdom “what if” reporting, this customer uncovered a backup job which was going to create a bottleneck if the consolidation took place exactly as planned.  So they found a less busy time of the day to run it, avoiding a potential problem.

They also found a number of no-longer-used reports that took server cycles and network bandwidth.  One of the reports created utilization on one link of approx 70% for just 2 minutes, and that alone was enough to increase transaction times well past an acceptable range.  By correlating metrics on the physical and virtual servers with link utilization, they were able to locate these rogue jobs and re-balance workloads.

Though the private cloud can help speed deployments and reduce costs, there’s little advantage to the end-user if it increases the risk to application performance and availability.  Through de-risking these areas, this customer was able to deliver the benefits of the new compute model and mitigate the risks.


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