Improving performance

Improving performance

This topic describes some approaches to improving performance. Click a heading to show or hide the contents.

Improving virtual hard disk performance

You can improve throughput for virtual hard disks by using the following techniques:

  • Use a hard disk solution that allows fast access, such as a SCSI hard disk, a redundant array of independent disks (RAID), or storage area network (SAN).
  • Put each virtual hard disk on a dedicated volume, SCSI hard disk, RAID, or SAN. It is easiest to put virtual hard disks together with their associated virtual machine configuration files on a RAID or SAN because this keeps everything in one place.
  • Put virtual hard disks on a different physical disk than the host operating system. In particular, you want to put virtual hard disks on a different physical disk than the host page file.
  • Reduce disk fragmentation. Defragment the physical disk on a regular basis, especially if you are using a dynamically expanding virtual hard disk. The data stored on a dynamically expanding virtual hard disk will grow increasingly fragmented as the size of the disk grows, because storage space is used only as it is needed. As the size grows it is less likely that the space will be contiguous. By contrast, a fixed-size virtual hard disk uses a reserved block of storage space, which means that data is less likely to be fragmented as it is stored.
  • Compact virtual hard disks to free more physical disk space.

For more information about improving virtual hard disk performance, see Optimizing virtual hard disks.

Improving network performance

You can improve network performance by using the following techniques:

  • Distribute the networking load. If you are running multiple instances of Virtual Server, you can distribute the networking load between them in the same manner as you would with physical servers. To do this, run a mix of network-intensive and non-network-intensive applications on a single instance of Virtual Server.
  • Add physical network adapters. For best performance, dedicate at least one physical network adapter to each virtual machine.
Virtual machines cannot take advantage of Network Load Balancing (NLB) because the Virtual Server network driver runs below the NLB driver in the host operating system network stack. This is to ensure that guest operating systems and the host operating system are isolated from one another and cannot can read, monitor, and capture one another's network traffic. Guest operating systems, however, that share the same virtual network can can read, monitor, and capture one another's network traffic. For more information about configuring a secure network, see Virtual network security. For more information about virtual network architecture, see Virtual network architecture. The location on the network of the Virtual Server service and the Web service with respect to one another is not a major performance consideration.

Improving processor performance

You can improve processor performance by using the following techniques:

  • Adjust the CPU allocation for virtual machines according to their CPU requirements. You can use monitoring software, such as Microsoft Operations Manager (MOM), to ascertain CPU utilization for each virtual machine. For more information about adjusting CPU allocation, see Configuring CPU resources for virtual machines.

Improving Virtual Server performance

You can improve the performance of Virtual Server by making the following configuration changes on the host operating system:

  • Increase the acceleration of your graphics hardware to full, as follows. On the Display control panel, click the Settings tab, and then click Advanced. Click the Troubleshoot tab, and then move the Hardware acceleration slider to Full.
  • Disable all unnecessary pointer options, such as pointer trails and shadow cursors, as follows. On the Mouse control panel, click the Pointer Options tab, and clear the check boxes of any options that you do not need.
  • Optimize system settings for performance, as follows. On the System control panel, click the Advanced tab. Under Performance, click Settings, and then click Adjust for best performance. Click the Advanced tab, select Background services, and then click OK twice.

You can improve the speed with which the Administration Website Master Status page displays and refreshes by hiding the virtual machine thumbnails that appear under Remote View. You can do this by clearing the Remote View check box on the Administration Website Properties page.

General recommendations

As with a physical computer, the overall objective in improving Virtual Server performance is to eliminate any performance bottlenecks. In general, the more processors, RAM, and hard disk space that exist, the better Virtual Server's performance will be.

We recommend that you overestimate the amount of RAM required to run the host operating system, Virtual Server, and the guest operating systems. Performance degrades when a virtual machine runs out of available RAM and starts paging. In addition, poor host operating system performance translates directly into poor virtual machine performance, so make sure you have more than enough RAM to run all host processes. We also recommend that you use fast hard disks and SANs to enhance virtual hard disk performance. For more information about estimating system requirements for the computer running Virtual Server, see System requirements for Virtual Server.

In addition, add network adapters to improve network performance—up to one per virtual machine. Finally, load-balance applications. Deploy applications that have similar resource requirements on different instances of Virtual Server. Mix network-intensive applications with those that are CPU-intensive and hard disk-intensive. This avoids excessive demands being made on a single system resource, such as processors.

If after taking steps to correct the situation, you find that Virtual Server performance still does not meet your requirements, you can easily migrate some of the virtual machines to a different instance of Virtual Server to balance the load. For more information, see Copying, managing, and renaming virtual machines.