1. www.metron-athene.com 5 Top Performance and Capacity Concerns for VMware Phil.Bell@metron-athene.com www.metron-athene.com

2. www.metron-athene.com Topics 1. Dangers with OS Metrics 2. Ready Time 3. Monitoring Memory 4. Disk Latency 5. Trending Clusters 3. www.metron-athene.com 1: Dangers with OS Metrics OS: 50% CPU Busy vmware: 25% CPU Busy Dormant/Idle OS: 50% CPU Busy vmware: 50% CPU Busy VM1 VM2 CPU: 1 Second 4. www.metron-athene.com OS vs vmware data 5. www.metron-athene.com Time Slicing Cores are shared between vCPUs in time slices 1 vCPU to 1 core at any point in time More vCPUs = More time slicing More time slicing = less accurate data from the OS Ignore OS metrics that involve time (Disk Occupancy is probably OK) Running Dormant/IdleVM1 VM1 6. www.metron-athene.com 2: Ready Time Ready Time VM wants to process, but cant Accumulated against VM More of a stack than a queue Contention for CPUs Performance impact How to avoid Ready Time Fewer vCPUs per VM Monitor: CPU Threads vs vCPUs & Ready Time 7. www.metron-athene.com Proportion of Time: 4 vCPU VM 8. www.metron-athene.com Proportion of Time: 2 vCPU VM 9. www.metron-athene.com IdleReadyThreads Ready Time 1 2 3 4 VM VM VM VM VM VM VM VM VM 10. www.metron-athene.com Ready Time Impacts on performance Monitor Ready Time as well as CPU % Avoid using high vCPU VMs 11. www.metron-athene.com 3: Monitoring Memory Tightest headroom in most clusters Not just a question of % used Reservations Limits Ballooning Shared Pages Active Memory Memory Available for VMs 12. www.metron-athene.com VM Memory Occupancy 13. www.metron-athene.com VM Memory Performance 14. www.metron-athene.com Cluster Memory 15. www.metron-athene.com 4: Storage Latency Why not KB/s or IO Time at the OS? Time slicing vmware has more detail 2 Levels of Interest Device Kernel 16. www.metron-athene.com Kernel 17. www.metron-athene.com Latency 18. www.metron-athene.com 5: Trending Clusters VMs have soft limits Resource Pools have soft limits Individual hosts are unimportant Want to know when youll run out of capacity? The hardware is the limit Trend hardware utilisation 19. www.metron-athene.com Trend 20. www.metron-athene.com Peak Hour Trend 21. www.metron-athene.com Cluster Ready Time 22. www.metron-athene.com Review 1. Dangers with OS Metrics Time slicing 2. Ready Time Delays processing vCPU vs Cores 3. Monitoring Memory Swap Allocated vs Active vs Consumed on Host 4. Disk Latency Device and Kernel 5. Trending Clusters Size of the cluster is the hard limit