to fragment, which reduces the I/O throughput when a single I/O is split into multiple I/Os. It has the lowest CPU overhead of the three VHD types because reads and writes do not need to look up the mapping of the block. Use fixed-size virtual hard drive (VHD) disks for From the Performance Tuning for Virtualization high disk I/O activities and configure disks for Servers section of the Performance Tuning data volumes using the SCSI controller. For Guidelines for Windows Server 2008 highly intensive storage I/O workloads that whitepaper available for download at : span multiple data drives, each VHD should be Synthetic SCSI Controller attached to a separate synthetic SCSI controller The synthetic storage controller provides for better overall performance. In addition, each significantly better performance on storage I/Os VHD should be stored on separate physical with reduced CPU overhead than the emulated disks. IDE device. The VM integration services include the enlightened driver for this storage device and are required for the operating system to detect it. The operating system disk must be mounted on the IDE device for the operating system to boot correctly, but the VM integration services load a filter driver that reroutes IDE device I/Os to the synthetic storage device. We strongly recommend that you mount the data drives directly to the synthetic SCSI controller because that configuration has reduced CPU overhead. You should also mount log files and the operating system paging file directly to the synthetic SCSI controller if their expected I/O rate is high. For highly intensive storage I/O workloads that span multiple data drives, each VHD should be attached to a separate synthetic SCSI controller for better overall performance. In addition, each VHD should be stored on separate physical disks. Use the SCSI controller to attach VHD for Even though Hyper-V IDE controller and SCSI high I/O activities, such as for SQL Server data controller offer comparable performance, the and log files. SCSI controller can only be installed if Hyper-V integration services are installed. Therefore, use of the SCSI controller to attach
to fragment, which reduces the I/O throughput when a single I/O is split into multiple I/Os. It has the lowest CPU overhead of the three VHD types because reads and writes do not need to look up the mapping of the block. Use fixed-size virtual hard drive (VHD) disks for high disk I/O activities and configure disks for data volumes using the SCSI controller. For highly intensive storage I/O workloads that span multiple data drives, each VHD should be attached to a separate synthetic SCSI controller for better overall performance. In addition, each VHD should be stored on separate physical disks. From the Performance Tuning for Virtualization Servers section of the Performance Tuning Guidelines for Windows Server 2008 whitepaper available for download at : Synthetic SCSI Controller The synthetic storage controller provides significantly better performance on storage I/Os with reduced CPU overhead than the emulated IDE device. The VM integration services include the enlightened driver for this storage device and are required for the operating system to detect it. The operating system disk must be mounted on the IDE device for the operating system to boot correctly, but the VM integration services load a filter driver that reroutes IDE device I/Os to the synthetic storage device. We strongly recommend that you mount the data drives directly to the synthetic SCSI controller because that configuration has reduced CPU overhead. You should also mount log files and the operating system paging file directly to the synthetic SCSI controller if their expected I/O rate is high. For highly intensive storage I/O workloads that span multiple data drives, each VHD should be attached to a separate synthetic SCSI controller for better overall performance. In addition, each VHD should be stored on separate physical disks. Use the SCSI controller to attach VHD for high I/O activities, such as for SQL Server data and log files. Even though Hyper-V IDE controller and SCSI controller offer comparable performance, the SCSI controller can only be installed if Hyper-V integration services are installed. Therefore, use of the SCSI controller to attach
BTS09HyperV.docx