Product Documentation

Workload Balancing Report Glossary

May 03, 2013
Important: Workload Balancing (WLB) and its functionality has been removed from XenServer version 6.2 and higher. Applications, code, or usage that depend WLB will not function in XenServer version 6.2 and higher. See CTX137333 for details.

This topic provides information about the following Workload Balancing reports.

Chargeback Utilization Analysis

You can use the Chargeback Utilization Analysis report ("chargeback report") to determine how much of a resource (such as a physical server) a specific department within your organization used. Specifically, the report shows information about all the virtual machines in your pool, including their availability and resource utilization. Since this report shows virtual machine availability ("up time"), it can help you demonstrate Service Level Agreements compliance and availability.

The chargeback report can help you implement a simple chargeback solution and facilitate billing. To bill customers for usage of a specific resource, generate the report, save it as Excel, and then customize the spreadsheet data to include your price per unit or import the Excel data into your billing system.

If you know that you will want to bill internal or external customers for virtual machine usage, consider incorporating department or customer names in your virtual machine naming conventions. This will make reading chargeback reports easier.

The resource reporting in the chargeback report is, in some cases, based on the allocation of physical resources to individual virtual machines.

Likewise, because XenServer lets you allocate fixed or automatic allocations of memory, the average memory data in this report is based on the amount of memory currently allocated to the virtual machine, whether it is through a fixed memory allocation or an automatically adjusting memory allocation (Dynamic Memory Control).

The chargeback report contains the following columns of data:

  • VM Name. The name of the virtual machine to which the data in the columns in that row applies.
  • VM Uptime. The number of minutes the virtual machine was powered on (or, more specifically, appears with a green icon beside it in XenCenter).
  • VCPU Allocation. The number of virtual CPUs configured on the virtual machine. Each virtual CPU receives an equal share of the physical CPU(s) on the host. For example, if you configured eight virtual CPUs on a host that contains two physical CPUs and this column had "1" in it, then this value is equal to 2/16 of the total processing power on the host.
  • Minimum CPU Usage (%). The lowest recorded value for virtual CPU utilization in the reporting period. This value is expressed as a percentage of the virtual machine's virtual CPU capacity, and the capacity is based on the number of virtual CPUs allocated to the virtual machine. For example, if, when you created the virtual machine, you allocated one virtual CPU to it, Minimum CPU Usage represents the lowest percentage of virtual CPU usage XenServer recorded, even if it was only for a second. If you allocated two virtual CPUs to the virtual machine, the value in this column represents the lowest usage of the combined capacity of both virtual CPUs, expressed as a percentage.

    Ultimately, the percentage of CPU usage represents the lowest recorded workload that virtual CPU handled. For example, if you allocate one virtual CPU to a virtual machine and the physical CPU on the host is 2.4 GHz, you are allocating one-eighth of 2.4 GHz to the virtual machine. This means that if the virtual machine's allocated capacity is 0.3GHz, or 300MHz, and the Minimum CPU Usage for the virtual machine was 20%, the virtual machine's lowest usage of the physical host's CPU during the reporting period was 60MHz.

  • Maximum CPU Usage (%). The highest percentage of the virtual machine's virtual CPU capacity that the virtual machine consumed during the reporting period. The CPU capacity consumed is a percentage of the virtual CPU capacity you allocated to the virtual machine. For example, if, when you created the virtual machine, you allocated one virtual CPU to it, the Maximum CPU Usage represents the highest recorded percentage of virtual CPU usage during the time reported. If you allocated two virtual CPUs to the virtual machine, the value in this column represents the highest utilization from the combined capacity of both virtual CPUs.
  • Average CPU Usage (%). Average CPU Usage (%). The average amount, expressed as a percentage, of the virtual machine's virtual CPU capacity that was in use during the reporting period. The CPU capacity is the virtual CPU capacity you allocated to the virtual machine. If you allocated two virtual CPUs to the virtual machine, the value in this column represents the average utilization from the combined capacity of both virtual CPUs.
  • Total Storage Allocation (GB). The amount of disk space that is currently allocated to the virtual machine at the time the report was run. Frequently, unless you modified it, this disk space is the amount of disk space you allocated to the virtual machine when you created it.
  • Virtual NIC Allocation. The number of virtual interfaces (VIFs) allocated to the virtual machine.
  • Current Minimum Dynamic Memory (MB).
    • Fixed memory allocation. If you assigned a virtual machine a fixed amount of memory (for example, 1024MB), the same amount of memory appears in the following columns: Current Minimum Dynamic Memory (MB), Current Maximum Dynamic Memory (MB), Current Assigned Memory (MB), and Average Assigned Memory (MB).
    • Dynamic memory allocation. If you configured XenServer to adjust a virtual machine's memory automatically based on a range (that is, you enabled Dynamic Memory Control), the minimum amount of memory specified in the range appears in this column. For example, if in the Memory Settings dialog box in XenCenter, you selected the Automatically allocate memory within this range option for this virtual machine and then specified the range values as 1024MB as the minimum memory and 2048MB as the maximum memory, then 1024MB will appear in the Current Minimum Dynamic Memory (MB) column.
  • Current Maximum Dynamic Memory (MB).
    • Dynamic memory allocation. If XenServer is set to adjust a VM's memory automatically based on a range, the maximum amount of memory specified in the range appears in this column. For example, if the memory range you provided was 1024MB minimum and 2048MB maximum, then 2048MB will appear in the Current Maximum Dynamic Memory (MB) column.
    • Fixed memory allocation. If you assign a VM a fixed amount of memory (for example, 1024MB), the same amount of memory appears in the following columns: Current Minimum Dynamic Memory (MB), Current Maximum Dynamic Memory (MB), Current Assigned Memory (MB), and Average Assigned Memory (MB).
  • Current Assigned Memory (MB).
    • Dynamic memory allocation. When Dynamic Memory Control is configured, this value indicates the amount of memory XenServer is currently allocating to the virtual machine at the time at which the report was run.
    • Fixed memory allocation. If you assign a virtual machine a fixed amount of memory (for example, 1024MB), the same amount of memory appears in the following columns: Current Minimum Dynamic Memory (MB), Current Maximum Dynamic Memory (MB), Current Assigned Memory (MB), and Average Assigned Memory (MB).
    Note: If you change the virtual machine's memory allocation immediately before running this report, the value reflected in this column reflects the new memory allocation you configured.
  • Average Assigned Memory (MB).
    • Dynamic memory allocation. When Dynamic Memory Control is configured, this value indicates the average amount of memory XenServer allocated to the virtual machine over the reporting period.
    • Fixed memory allocation. If you assign a virtual machine a fixed amount of memory (for example, 1024MB), the same amount of memory appears in the following columns: Current Minimum Dynamic Memory (MB), Current Maximum Dynamic Memory (MB), Current Assigned Memory (MB), and Average Assigned Memory (MB).
    Note: If you change the virtual machine's memory allocation immediately before running this report, the value displayed in this column may not change from what it would have previously displayed. The value in this column reflects the average over the time period.
  • Average Network Reads (BPS). The average amount of data (in bits per second) the virtual machine received during the reporting period.
  • Average Network Writes (BPS). The average amount of data (in bits per second) the virtual machine sent during the reporting period.
  • Average Network Usage (BPS). The combined total (in bits per second) of the Average Network Reads and Average Network Writes. For example, if a virtual machine sent, on average, 1,027 bits per second and received, on average, 23,831 bits per second over the reporting period, then the Average Network Usage would be the combined total of these two values: 24,858 bits per second.
  • Total Network Usage (BPS). The total of all network read and write transactions in bits per second over the reporting period.

Host Health History

This report displays the performance of resources (CPU, memory, network reads, and network writes) on specific host in relation to threshold values.

The colored lines (red, green, yellow) represent your threshold values. You can use this report with the Pool Health report for a host to determine how a particular host's performance might be affecting overall pool health. When you are editing the performance thresholds, you can use this report for insight into host performance.

You can display resource utilization as a daily or hourly average. The hourly average lets you see the busiest hours of the day, averaged, for the time period.

To view report data grouped by hour, expand + Click to view report data grouped by house for the time period under the Host Health History title bar.

Workload Balancing displays the average for each hour for the time period you set. The data point is based on a utilization average for that hour for all days in the time period. For example, in a report for May 1, 2009 to May 15, 2009, the Average CPU Usage data point represents the resource utilization of all fifteen days at 12:00 hours combined together as an average. That is, if CPU utilization was 82% at 12 PM on May 1st, 88% at 12 PM on May 2nd, and 75% on all other days, the average displayed for 12 PM is 76.3%.

Pool Optimization Performance History

The optimization performance report displays optimization events (that is, when you optimized a resource pool) against that pool's average resource usage. Specifically, it displays resource usage for CPU, memory, network reads, and network writes.

The dotted line represents the average usage across the pool over the period of days you select. A blue bar indicates the day on which you optimized the pool.

This report can help you determine if Workload Balancing is working successfully in your environment. You can use this report to see what led up to optimization events (that is, the resource usage before Workload Balancing recommended optimizing).

This report displays average resource usage for the day; it does not display the peak utilization, such as when the system is stressed. You can also use this report to see how a resource pool is performing if Workload Balancing is not making optimization recommendations.

In general, resource usage should decline or be steady after an optimization event. If you do not see improved resource usage after optimization, consider readjusting threshold values. Also, consider whether or not the resource pool has too many virtual machines and whether or not new virtual machines were added or removed during the time frame you specified.

Pool Audit Trail

This report displays the contents of the XenServer Audit Log, a XenServer feature designed to log attempts to perform unauthorized actions and select authorized actions, including import/export, host and pool backups, and guest and host console access. The report gives more meaningful information when XenServer administrators are given their own user accounts with distinct roles assigned to them using the Role-Based Access Control feature. For information about the Audit Log feature, see the audit log documentation in the Workload Balancing Administrator's Guide.

Important: To run the audit log report, the Audit Logging feature must be enabled. By default, the Audit Log is always enabled in the Workload Balancing virtual appliance. However, the audit log only captures limited amounts of data for specific objects and actions.

This report displays the following:

  • Time. The time XenServer recorded the user's action.
  • Event Action. The action that occurred. For definitions of these actions, see Audit Log Event Names.
  • User Name. The name of the person who created the session in which the action was performed. In some cases, this may be the User ID.
  • Access. Whether or not the user had permission to perform the action.
  • Event Object. The object that was the subject of the action (for example, a virtual machine).
  • Object Name. The name of the object (for example, the name of the virtual machine).
  • Succeeded. This provides the status of the action (that is, whether or not it was successful).

Pool Health

The pool health report displays the percentage of time a resource pool and its hosts spent in four different threshold ranges: Critical, High, Medium, and Low. You can use the Pool Health report to evaluate the effectiveness of your performance thresholds.

A few points about interpreting this report:

  • Resource utilization in the Average Medium Threshold (blue) is the optimum resource utilization regardless of the placement strategy you selected. Likewise, the blue section on the pie chart indicates the amount of time that host used resources optimally.
  • Resource utilization in the Average Low Threshold Percent (green) is not necessarily positive. Whether Low resource utilization is positive depends on your placement strategy. For example, if your placement strategy is Maximum Density and most of the time your resource usage was green, Workload Balancing might not be fitting the maximum number of virtual machines possible on that host or pool. If this is the case, you should adjust your performance threshold values until the majority of your resource utilization falls into the Average Medium (blue) threshold range.
  • Resource utilization in the Average Critical Threshold Percent (red) indicates the amount of time average resource utilization met or exceeded the Critical threshold value.

If you double-click on a pie chart for a host's resource usage, XenCenter displays the Host Health History report for that resource (for example, CPU) on that host. Clicking the Back to Parent Report toolbar button returns you to the Pool Health history report. Note: This button is only available in drill-through reports, such as the Pool Health report.

If you find the majority of your report results are not in the Average Medium Threshold range, you probably need to adjust the Critical threshold for this pool. While Workload Balancing provides default threshold settings, these defaults are not effective in all environments. If you do not have the thresholds adjusted to the correct level for your environment, Workload Balancing's optimization and placement recommendations might not be appropriate. For more information, see Changing the Critical Thresholds.

Note: The High, Medium, and Low threshold ranges are based on the Critical threshold value.

Pool Health History

This report provides a line graph of resource utilization on all physical hosts in a pool over time. It lets you see the trend of resource utilization - if it tends to be increasing in relation to your thresholds (Critical, High, Medium, and Low). You can evaluate the effectiveness of your performance thresholds by monitoring trends of the data points in this report.

Workload Balancing extrapolates the threshold ranges from the values you set for the Critical thresholds. Although similar to the Pool Health report, the Pool Health History report displays the average utilization for a resource on a specific date rather than the amount of time overall the resource spent in a threshold.

With the exception of the Average Free Memory graph, the data points should never average above the Critical threshold line (red). For the Average Free Memory graph, the data points should never average below the Critical threshold line (which is at the bottom of the graph). Because this graph displays free memory, the Critical threshold is a low value, unlike the other resources.

A few points about interpreting this report:

  • When the Average Usage line in the chart approaches the Average Medium Threshold (blue) line, it indicates the pool's resource utilization is optimum regardless of the placement strategy configured.
  • Resource utilization approaching the Average Low Threshold (green) is not necessarily positive. Whether Low resource utilization is positive depends on your placement strategy. For example, if your placement strategy is Maximum Density and most days the Average Usage line is at or below the green line, Workload Balancing might not be placing virtual machines as densely as possible on that pool. If this is the case, you should adjust the pool's Critical threshold values until the majority of its resource utilization falls into the Average Medium (blue) threshold range.
  • When the Average Usage line intersects with the Average Critical Threshold Percent (red), this indicates the days when the average resource utilization met or exceeded the Critical threshold value for that resource.

If you find the data points in the majority of your graphs are not in the Average Medium Threshold range, but you are satisfied with the performance of this pool, you might need to adjust the Critical threshold for this pool. For more information, see Changing the Critical Thresholds.

Pool Optimization History

The Pool Optimization History report provides chronological visibility into Workload Balancing optimization activity.

Optimization activity is summarized graphically and in a table. Drilling into a date field within the table displays detailed information for each pool optimization performed for that day.

This report lets you see the following information:

  • VM Name. The name of the virtual machine that Workload Balancing optimized.
  • Reason. The reason for the optimization.
  • Status. If the optimization was successful.
  • From Host. The physical server where the virtual machine was originally hosted.
  • To Host. The physical server where the virtual machine was moved.
  • Time. The time when the optimization occurred.
Tip: You can also generate a Pool Optimization History report from the WLB tab, by clicking the View History link.

Virtual Machine Motion History

This line graph displays the number of times virtual machines moved on a resource pool over a period of time. It indicates if a move resulted from an optimization recommendation and to which host the virtual machine moved. This report also indicates the reason for the optimization. You can use this report to audit the number of moves on a pool.

Some points about interpreting this report:

  • The numbers on the left side of the chart correspond with the number of moves possible, which is based on how many virtual machines are in a resource pool.
  • You can look at details of the moves on a specific date by expanding the + sign in the Date section of the report.

Virtual Machine Performance History

This report displays performance data for each virtual machine on a specific host for a time period you specify. Workload Balancing bases the performance data on the amount of virtual resources allocated for the virtual machine. For example, if the Average CPU Usage for your virtual machine is 67%, this means that your virtual machine was using, on average, 67% of its virtual CPU for the period you specified.

The initial view of the report displays an average value for resource utilization over the period you specified.

Expanding the + sign displays line graphs for individual resources. You can use these graphs to see trends in resource utilization over time.

This report displays data for CPU Usage, Free Memory, Network Reads/Writes, and Disk Reads/Writes.