Many organizations today have a ROBO environment with local IT infrastructure. These remote locations usually have anywhere from a few servers running a few workloads to support local needs, to numerous servers spanning a large-scale datacenter. The distributed and remote nature of this infrastructure makes it hard to manage, difficult to protect, and costly to maintain. Further, the remote nature of servers makes it more challenging to perform important VM/host-related operations.
vSphere is designed to address these ROBO use cases, including IT infrastructure located in remote, distributed sites. VMware vCenter Server provides a centralized way to control and monitor the virtual infrastructure, including ESXi hosts, virtual machines, storage, and networking resources. It has been widely deployed in a ROBO environment to manage ESXi hosts that are distributed over large geographical distances over a wide range of networks with different network characteristics, including low/high bandwidth, network latency, and packet error rates. In the paper, we test:
LAN with high-bandwidth and low-latency links.
WAN with low-bandwidth and high-latency links.
Various networks in between; for example, DSL, T1, 4G, 5G, …
We demonstrate that vCenter Server performs well in the ROBO environment for both network bandwidth use, as well as virtual machine and ESXi host task execution times. Instead of a bandwidth restriction, we observe that network latency has a bigger impact on the overall performance. As the network latency between vCenter Server and ESXi hosts increases, the average operation latency also increases. The experimental results also show how efficiently vCenter Server executes VM operations in high-latency networks: The average VM operation execution time increases much more slowly when network latency increases by several times.
High availability (aka HA) services are important in any platform, and VMware vCenter Server® is no exception. As the main administrative and management tool of vSphere, it is a critical element that requires HA. vCenter Server HA (aka VCHA) delivers protection against software and hardware failures with excellent performance for common customer scenarios, as shown in this paper.
Much work has gone into the high availability feature of VMware vCenter Server® 6.5 to ensure that this service and its operations minimally affect the performance of your vCenter Server and vSphere hosts. We thoroughly tested VCHA with a benchmark that simulates common vCenter Server activities in both regular and worst case scenarios. The result is solid data and a comprehensive performance characterization in terms of:
Performance of VCHA failover/recovery time objective (RTO): In case of a failure, vCenter Server HA (VCHA) provides failover/RTO such that users can continue with their work in less than 2 minutes through API clients and less than 4 minutes through UI clients. While failover/RTO depends on the vCenter Server configuration and the inventory size, in our tests it is within the target limit, which is 5 minutes.
Performance of enabling VCHA: We observed that enabling VCHA would take around 4 – 9 minutes depending on the vCenter Server configuration and the inventory size.
VCHA overhead: When VCHA is enabled, there is no significant impact for vCenter Server under typical load conditions. We observed a noticeable but small impact of VCHA when the vCenter Server was under extreme load; however, it is unlikely for customers to generate that much load on the vCenter Server for extended time periods.
Performance impact of vCenter Server statistics level: With an increasing statistics level, vCenter Server produces less throughput, as expected. When VCHA is enabled for various statistics levels, we observe a noticeable but small impact of 3% to 9% on throughput.
Performance impact of a private network: VCHA is designed to support LAN networks with up to 10 ms latency between VCHA nodes. However, this comes with a performance penalty. We study the performance impact of the private network in detail and provide further guidelines about how to configure VCHA for the best performance.
External Platform Services Controller (PSC) vs Embedded PSC: We study VCHA performance comparing these two deployment modes and observe a minimal difference between them.
Throughout the paper, our findings show that vCenter Server HA performs well under a variety of circumstances. In addition to the performance study results, the paper describes the VCHA architecture and includes some useful performance best practices for getting the most from VCHA.
Better performance, lower latency, and streamlined statistics are just some of the new features you can expect to find in the vCenter Server in version 5.1. The VMware performance team has published a paper about vCenter Server 5.1 database performance in large environments. The paper shows that statistics collection creates the biggest performance impact on the vCenter Server database. In vSphere 5.1, several aspects of statistics collection have been changed to improve the overall performance of the database. There were three sources of I/O to the statistics tables in vCenter Server—inserting statistics, rolling up statistics between different intervals, and deleting statistics when they expire. These activities have been improved by changing the way the relevant data is persisted to the tables, by partitioning the tables instead of using staging tables. In addition, by removing the staging tables, statistics collection is more robust, resolving the issues described in KB 2011523 and KB 1003878. Scalability is also improved by allowing larger inventories to be supported because they don’t take so long to read/write data from the old staging tables. The paper also includes best practices to take advantage of these changes in environments where vCenter Server has a large inventory. For more details, see vCenter Server 5.1 Database Performance in Large-Scale Environments.
Here are the URLs for the paper, “VMware vCenter Server 5.1 Database Performance Improvements and Best Practices for Large-Scale Environments”: