Round Rock-based Dell said this morning that it has acquired AppAssure, a provider of backup and recovery software for virtual servers. Financial terms of the buy were not announced. AppAssure provides a service which provides backup and recovery of virtual servers such as VMware, Hyper-V, and XenServer. The firm is based in Reston, Virginia, and was venture backed by Bain Capital Ventures. Dell said the buy will bolster both its storage and software strategy. Dell explained that AppAssure recently reported 194 percent revenue growth, year-over-year, and has 19 consecutive quarters of growth. AppAssure had approximately 230 employees, which Dell said it would retain, in addition to investing in additional engineering and sales capability.