Object-Based Storage Devices (OSDs) offer an object-based data layout instead of using the traditional block-based design. Object storage ideas are increasingly being used in parallel file systems and cloud storage. Previous work has implemented the Parallel Virtual File System (PVFS) on OSDs by moving the metadata and data operations to the OSDs. In this paper, we present two new methods to further improve the performance of the existing PVFS-OSD implementation. These methods are using object collections to represent traditional directories on OSDs and delaying the creation of an OSD object until it is accessed by a write operation. The optimization methods are not particular to PVFS-OSD implementation and could be used with other parallel file systems-object storage implementations too. Experimental evaluations show that using collections yields up to 29 times of improvement in throughput; whereas delaying the creation of OSD objects provides 25% throughput improvement.