| | 1 | * __'''NFS:'''__ |
| | 2 | * Primary file system for clusters, and is pretty much” plug and play” on most *nix systems. |
| | 3 | * It was the first popular file system that allowed distributed systems to share data. |
| | 4 | * __'''NFSv3:'''__ |
| | 5 | * The most popular version of NFS. It was released around 1995 and |
| | 6 | * added several features including support for 64-bit file sizes and offsets (so it can handle files larger than 4GB), asynchronous write support, and TCP as a transport layer. |
| | 7 | * __'''NFSv4:'''__ |
| | 8 | * Around 2003, NFSv4 was released with some improvements. In particular, |
| | 9 | * it added some speed improvements, strong security (with compatibility for multiple security protocols), and NFS became a stateful protocol. |
| | 10 | * __'''NFS 的效能面：'''__ |
| | 11 | * The good news for NFS and NAS is that many codes don’t require lots of I/O for good performance. These codes will run very well using NFS as the storage protocol even for large runs (100+ nodes or several hundred cores). NFS provides adequate performance until the input and output files for these codes become extremely large, or if the code is run across a very large number of processors (in the thousands). |
| | 12 | * NFS still lacks the performance and scalability required by many large clusters, but that is about to change. |
| | 13 | * __'''pNFS (NFSv4.1):'''__ |
| | 14 | * adding '''''PFS capability to the NFS protocol'''''. The goal is to improve '''''performance and scalability''''' while making the changes within a standard (recall that NFS is the only true shared file system standard). |
| | 15 | * this standard is designed to be used with file based, block based, and object based storage devices with an eye towards freeing customers from vendor lock-in. |
| | 16 | * pNFS Architecture, [[Image(pNFS_arch.png)]] |
| | 17 | * pNFS Sever 連接 Client 和 Storage ，當 Client 要存取檔案時先至 pNFS Server 查詢 Metadata 找到檔案的位置，再連接到存放檔案的 Sotrage |
