Abstract: A customer of a computing resource service provider submits a request to a virtual computer system service to instantiate a virtual computer system. In response to the request, the service obtains physical network information in order to identify any hardware groupings that may be used, at a later time, to provision one or more data storage volumes that may be associated with the virtual computer system. The service assigns a score to each of these hardware groupings based at least in part on the available capacity for provisioning of these data storage volumes. Based at least in part on these assigned scores, the virtual computer system service selects a hardware grouping and instantiates the virtual computer system within the selected hardware grouping.