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How to Resolve Bottlenecks and
Optimize your Virtual Environment
Chris Chesley, Sr. Systems [email protected]
Today’s Objectives
Overview of the problems often encountered in a virtual environment.
How to identify current performance bottlenecks
How to find capacity in your environment
How to optimize your virtual machines
How to identify wasted storage
New vs. Old Data Center
Pre-Virtualized Data Center• One application – One server• No sharing of memory and CPU• Limited sharing of storage
Virtualized Datacenter• Shared memory and CPU • Massively shared storage• Performance = capacity• Vmotion/DRS – Dynamic nature• Change from known to unknown state when VM added or changed
Takeaway
If not closely monitored and managed, sharing of resources will lead to performance problems and downtime.
Resource Utilization
What’s shared Physical CPU / Cores (not sockets)
Physical Memory
Physical Disk Storage (how many GB am I using) I/O (reads, writes, disk latency, disk queue latency)
Physical Network
Capacity issues occur at any level or resource type VMs Host Cluster Resource Pools (Vmware only) Data Center
Boundaries in Virtual Environments
How to Identify Current Capacity Bottlenecks
Out of the box Management consoles: vCenter client (Vmware) and Hyper-V Manager or Virtual Machine Manager (Hyper-V):Real time per-host stats, per-cluster, and per-VM statistics
Esxtop (Vmware) or PerfMon (Hyper-V): per-host statistics
VIM API and SDK: allows software to collect only the statistics they want
Performance Monitoring Options
For every Cluster, Resource Pool, Host, and VM, using VirtualCenter to examine memory, storage, CPU and network utilization over a period of at least 1 week
Very time consuming process– (Clusters + Resource Pools + Hosts + VMs) X 5 resources (CPU, storage,
RAM, network, disk i/o) = # of charts to review– e.g. (3 Clusters +3 RPs+ 50 Hosts + 500 VMs) X 5 = 2,780 charts to examine
Requires ongoing attention: at least several times a week
Select a Cluster, Resource Pool, or a Host
Get info on available memory, storage, CPU, disk i/o, and network i/o
Calculate an average VM footprint Memory, CPU, storage, disk i/o
Where do I put new VMs?
Identifying Available Resource Capacity
Apply an average VM footprint to every resource type to see which resource you will run out of first
That’s how many more VMs you can fit into Hosts, Clusters, or Resource Pools
Where do I place new VMs
Data Center view – Active/Active DR Data Centers may have capacity
Identifying Available Resource Capacity
Model additions of new VMs Understand current utilization on all resource
types Make necessary changes to compensate for
current and future growth
Implement iron clad change control process Maintenance window and workload
requirements Cluster failover configuration Resource Pool configuration Powered down VMs
Predicting Future Capacity Bottlenecks
Optimize your virtual machines• Very easy to create VMs, not easy to know how many
resources to give them.• No automated clean up• According to the
Information Technology Infrastructure Library (ITIL), capacity management is the discipline that ensures IT infrastructure is used in the most efficient, predictable and cost-effective manner.
• Goal of capacity management: Finding the balance between density and performance.
Defining which Metrics to Monitor
Allocated vs. consumed resources.
CPU: The important metric to measure is CPU utilization.
Memory: Use memory consumed in most cases when evaluating memory utilization.
Memory consumed measures how much memory each VM is using on the physical host minus an memory that is shared by other VMs.
Storage: The best way to monitor storage is to look at each vmdk file from the guest OS perspective and look at utilization.
Identifying Allocated Resources
Allocated resources, limits and reservation info can be easily collected from vCenter or a 3rd party solution.
Defining your Evaluation Period
Time period: You need to decide how much data you need to analyze when computing the average or peak values to make sure that it captures your busy periods or is a good representation of your business cycles.
Priority: Many administrators will divide up their systems into high, medium and low priorities with different metrics for each group.
Computing Resources Consumed
The next step is to look at each resource and compute the average or peak utilization for your evaluation period.
Generate Recommendations
The next step is to put all the pieces together and evaluate each resource for each VM and determine if the right amount of CPU, Memory and Storage has been assigned to the VM.
Wasted Storage
• Easy to create VMs• VMs are large files• Not always easy to find any files that are not being
used.
Types of Wasted Storage
• Abandoned VMs – A virtual machine file that is on your datastore but is not attached to a VM listed in vCenter or the host.
• Powered off VMs• Templates Not used in 30 days or more• Snapshots• Zombie VMs – A virtual machine that is running but
not being used.
Wasted Storage
Abandoned VMs
Powered off VMs
Manual or Automated?
VKernel’s Optimization Pack and Capacity Analyzer does this work for you.
Conclusion
The goal of virtualization is to find the balance between correctly sizing your environment while achieving maximum performance with the least amount of resources.
Download a trial of VKernel’s appliances to resolve Performance bottlenecks and optimize your environment!
http://www.vkernel.com