Can I Use the Same Drive for Multiple OSDs¶
Yes. Please don’t do this! Except for initial evaluations of Ceph, we do not recommend running multiple OSDs on the same drive. In fact, we recommend exactly the opposite. Only run one OSD per drive. For better performance, run journals on a separate drive from the OSD drive, and consider using SSDs for journals. Run operating systems on a separate drive from any drive storing data for Ceph.
Storage drives are a performance bottleneck. Total throughput is an important consideration. Sequential reads and writes are important considerations too. When you run multiple OSDs per drive, you split up the total throughput between competing OSDs, which can slow performance considerably.