Enhanced vMotion Compatibility (EVC) is a technique that allows vMotion to proceed even when ESXi hosts with CPUs of different technologies exist in the vMotion destination cluster. EVC assigns a baseline to all ESXi hosts in the destination cluster so that all of them will be compatible for vMotion. An example is assigning a Nehalem baseline to a cluster mixed with ESXi hosts with Westmere, Nehalem processors. In this case, the features available in Westmere would be hidden, because it is a newer processor than Nehalem. But all ESXi hosts would “broadcast” that they have Nehalem features.
Tests showed how utilizing EVC with different applications affected their performance. Several workloads were chosen to represent typical applications running in enterprise datacenters. The applications represented included database, Java, encryption, and multimedia. To see the results and learn some best practices for performance with EVC, read Impact of Enhanced vMotion Compatibility on Application Performance.
A new version of Performance Best Practices for vSphere is now available. This is a book designed to help system administrators obtain the best performance from vSphere deployments.
We've addressed many of the new features in vSphere 5.0 from a performance perspective. These include:
- Storage Distributed Resource Scheduler (Storage DRS), which performs automatic storage I/O load balancing
- Virtual NUMA, allowing guests to make efficient use of hardware NUMA architecture
- Memory compression, which can reduce the need for host-level swapping
- Swap to host cache, which can dramatically reduce the impact of host-level swapping
- SplitRx mode, which improves network performance for certain workloads
- VMX swap, which reduces per-VM memory reservation
- Multiple vMotion vmknics, allowing for more and faster vMotion operations
We've also significantly updated and expanded many of the topics we've covered in previous editions of the book. These include:
- Choosing hardware for a vSphere deployment
- Configuring ESXi for best performance
- Guest operating system performance
- vCenter and vCenter database performance
- vMotion and Storage vMotion performance
- Distributed Resource Scheduler (DRS) and Distributed Power Management (DPM) performance
- High Availability (HA), Fault Tolerance (FT), and VMware vCenter Update Manager performance
The book can be found at: Performance Best Practices for VMware vSphere 5.0.