1. Performance and Capacity Management of DRS Clusters Anne Holler, VMware Ganesha Shanmuganathan, VMware VSVC5821 #VSVC5821

2. 2 Disclaimer This session may contain product features that are currently under development. This session/overview of the new technology represents no commitment from VMware to deliver these features in any generally available product. Features are subject to change, and must not be included in contracts, purchase orders, or sales agreements of any kind. Technical feasibility and market demand will affect final delivery. Pricing and packaging for any new technologies or features discussed or presented have not been determined. 3. 3 DRS = Distributed Resource Scheduler The overall design goals of DRS are: Optimize VM performance subject to user control settings Provide resource isolation and sharing for subsets of VMs Use infrastructure and management resources efficiently Provide comprehensive automatic cluster management Mechanisms: Initial placement / Load balancing QoS enforcement: shares, reservations, limits, resource pools Policy enforcement: Affinity Rules, Anti-Affinity Rules Evacuation for host maintenance VM VM VM ESX Server VM ESX Server VM VM VM ESX Server VMVM VMVM DRS Cluster 4. 4 Key elements to achieve design goals Computing/Delivering VM CPU & memory resource entitlements (Automatic VM Initial placement and automatic Migration) Mapping the cluster resource pool tree onto individual hosts Modeling vMotion remediation costs Respecting constraints: compatibility, availability, host state, rules Lets look at each of these elements and examine advanced deployment situations for each along with tips to handle them 5. 5 DRS Advanced Options 6. 6 Computing/Delivering VM CPU and Memory resource entitlements 7. 7 VM's dynamic entitlement (DE) is what VM would get if cluster were one giant host Takes into account VM resource controls and demand Dynamic Entitlement 1 giant host CPU = 60 GHz Memory = 384 GB 6 hosts, each: CPU = 10 GHz Memory = 64 GB 8. 8 VM Resource Controls Reservation: Guaranteed allocation Limit: Guaranteed upper bound Shares: Allocation in between Resource pools: allocation and isolation for groups of VMs Actual allocation depends on the shares and demand Configured (8GB) Limit (6GB) Actual(5GB) Reserved (1GB) 0 9. 9 CPU Entitlement: Close-up on CPU Demand Estimate By ESX: CPU Demand = used + stolen * run / (run + sleep) Stolen time includes: ready: vCPU is runnable but target CPU is busy overlap: Use of CPU to handle interrupts during this vCPU execution hyperthreading: Impact on CPU operation due to use of partner CPU power management: Loss of CPU cycles due to platform frequency scaling http://www.vmware.com/files/pdf/techpaper/VMware-vSphere-CPU-Sched-Perf.pdf By DRS: CPU Demand = ESX CPU Demand over time load balancing: average over last 5 minutes cost/benefit & DPM: maximum over extended period (up to 60 minutes) 10. 10 CPU Entitlement: Satisfies VM demand unless Contention Contention monitoring: Ready time Rule of thumb: Ready