is stored on the virtual start as zeroed blocks If performance is not a machine itself. This but are not backed by concern, for instance accommodates the any actual space in in a development most efficient use of the VHD file. Reads environment, this may available storage. from such blocks be a suitable option for return a block of zeros. the operating system When a block is first hard drives. written to, the Causes additional virtualization stack CPU overhead due to must allocate space block mapping lookup. within the VHD file for the block and then update the corresponding metadata. In addition to this every time an existing block is referenced the block mapping must be looked up in the metadata. This increases the number of read and write activities which in turn causes increased CPU utilization. The dynamic growth also requires that the server administrator monitor disk capacity to ensure that is sufficient disk storage as the storage requirements increase. Differencing disks This a Performance can A amount of configuration where the degrade because machine specific differencing disk stores read/writes need to configuration is all changes relative to access the required for BizTalk a base VHD and the parent Server 2009 base VHD remains VHD as well as the installations and child
is stored on the virtual machine itself. This accommodates the most efficient use of available storage. start as zeroed blocks but are not backed by any actual space in the VHD file. Reads from such blocks return a block of zeros. When a block is first written to, the virtualization stack must allocate space within the VHD file for the block and then update the corresponding metadata. In addition to this every time an existing block is referenced the block mapping must be looked up in the metadata. This increases the number of read and write activities which in turn causes increased CPU utilization. The dynamic growth also requires that the server administrator monitor disk capacity to ensure that is sufficient disk storage as the storage requirements increase. If performance is not a concern, for instance in a development environment, this may be a suitable option for the operating system hard drives. Causes additional CPU overhead due to block mapping lookup. Differencing disks This a configuration where the differencing disk stores all changes relative to a base VHD and the base VHD remains Performance can degrade because read/writes need to access the parent VHD as well as the A amount of machine specific configuration is required for BizTalk Server 2009 installations and child
BTS09HyperV.docx