As vendors try to showcase their products, there is often confusion regarding the difference between two similar products, such as PanFS from Panasas, Inc. and Lustre (from Sun, then Oracle, then Whamcloud, then Intel). But in this particular case, the difference is not that big — you will see for yourself.
Panasas was founded in 1999 by Dr. Garth A. Gibson and Dr. William Courtright. Garth A. Gibson is a co-inventor of RAID technology — no wonder that his company excels in storage products. Panasas provides appliances — hardware and software bundled together and fine-tuned for high performance. This has always been a “closed-source”, proprietary product, which translates into a vendor lock-in.
Lustre experienced a tumultuous history of corporate mergers and acquisitions. Finally, source code was published under the GNU GPL license, but only the chosen few would dare to look inside. Everyone else is happy with pre-patched Linux kernels. Most development efforts seem to be done by Whamcloud, because they have the necessary expertise. Recently, Whamcloud was acquired by Intel. Theoretically, Lustre is still open source, so anyone can contribute, but for practical purposes, you still need to ask a single company (formerly Whamcloud, and now Intel) if you want to have new features added.
Similarity between the Panasas solution and Lustre is best represented by this figure taken from the Lustre manual:
To put it simply, when a client (on the left) wants to read a file, it sends the file name to a metadata server (green circle on the top). The metadata server responds with the location of the parts of that file on several storage servers (two green circles on the right). Then the client can query storage servers directly via a high-performance network and retrieve file parts. The idea is both simple and brilliant (and it’s called object-based storage).
So, that’s how Lustre works. But if we look at Panasas® ActiveStor™ appliance, it is not so different. Their director blades correspond to metadata servers in Lustre, and storage blades correspond to object storage servers. One shelf of ActiveStor (4U height) contains 11 blades, of them 1, 2 or 3 are director blades, and the rest are storage blades (in additional expansion shelves, all 11 blades are storage blades). It is still the old good object storage architecture, simply it is slightly disguised by the physical packaging.
Panasas ActiveStor has more features, such as per-file RAID, or the ability to use many director blades simultaneously. For comparison, Lustre currently only supports one metadata server (MDS) per filesystem, or two MDSs in an Active/Passive failover configuration. On the other side, Lustre is known to provide superior performance, up to 1,3 terabytes per second with the IBM Sequoia supercomputer — no Panasas-based storage solution of comparable scale was ever built.
Additionally, Lustre can use any hardware of your choice for servers and storage devices. This can be a benefit if you want more flexibility, but it can turn against you if you need to debug your custom configuration — a problem that you won’t have with Panasas. The choice is yours!