The increasing expansion of data scale leads to the widespread deployment of storage systems with larger capacity and further induces the climbing probability of data loss or damage. The Maximum Distance Separable (MDS) code in RAID-6, which tolerates the concurrent failures of any two disks with minimal storage requirement, is one of the best candidates to enhance the data reliability. However, most of the existing works in this literature are more inclined to be specialized and cannot provide a satisfied performance under an all-round evaluation. Aiming at this problem, we propose an all-round MDS code named Horizontal-Vertical Code (HV Code) by taking advantage of horizontal parity and vertical parity. HV Code achieves the perfect I/O balancing and optimizes the operation of partial stripe writes, while preserving the optimal encoding/decoding/update efficiency. Moreover, it owns a shorter parity chain which grants it a more efficient recovery for single disk failure. HV Code also behaves well on degraded read operation and accelerates the reconstruction of double disk failures by executing four recovery chains in parallel. The performance evaluation demonstrates that HV Code well balances the I/O distribution. HV Code also eliminates up to 32.2 percent I/O operations for partial stripe writes in read-modify-write mode, and reduces up to 28.9 percent I/O operations for partial stripe writes in reconstruct-write mode. Moreover, HV Code reduces 5.4 $\sim$<alternatives> <inline-graphic xlink:type="simple" xlink:href="shen-ieq1-2464800.gif"/></alternatives>39.8 percent I/O operations per element for the single disk reconstruction, decreases 8.3$\sim$ <alternatives><inline-graphic xlink:type="simple" xlink:href="shen-ieq2-2464800.gif"/></alternatives>39.0 percent I/O operations for degraded read operations, and shortens 47.4$\sim$ <alternatives><inline-graphic xlink:type="simple" xlink:href="shen-ieq3-2464800.gif"/></alternatives>59.7 percent recovery time for double disk recovery.