|
AFS |
NFS |
File Access |
Common name space from all workstations |
Different file names from different workstations |
File Location Tracking |
Automatic tracking by file system processes and databases |
Mountpoints to files set by administrators and users |
Performance |
Client caching to reduce network load; callbacks to maintain cache consistency |
No local disk caching; limited cache consistency |
Andrew Benchmark (5 phases, 8 clients) |
Average time of 210 seconds/client |
Average time of 280 seconds/client |
Scaling capabilities |
Maintains performance in small and very large installations |
Best in small to mid-size installations |
|
Excellent performance on wide-area configuration |
Best in local-area configurations |
Security |
Kerberos mutual authentication |
Security based on unencrypted user ID's |
|
Access control lists on directories for user and group access |
No access control lists |
Availability |
Replicates read-mostly data and AFS system information |
No replication |
Backup Operation |
No system downtime with specially developed AFS Backup System |
Standard UNIX backup system |
Reconfiguration |
By volumes (groups of files) |
Per-file movement |
|
No user impact; files remain accessible during moves, and file names do not change |
Users lose access to files and filenames change (mountpoints need to be reset) |
System Management |
Most tasks performed from any workstation |
Frequently involves telnet to other workstations |
Autonomous Architecture |
Autonomous administrative units called cells, in addition to file servers and clients |
File servers and clients |
|
No trust required between cells |
No security distinctions between sites |
|
[ source: ftp://ftp.transarc.com/pub/afsps/doc/afs-nfs.comparison ] |
Other points:
- Some vendors offer more secure versions of NFS but implementations vary. Many NFS ports have no extra security features (such as Kerberos).
- The AFS Cache Manager can be configured to work with a RAM (memory) based cache. This offers signifigant performance benefits over a disk based cache. NFS has no such feature. Imagine how much faster it is to access files cached into RAM!
- The Andrew benchmark demonstrates that AFS has better performance than NFS as the number of clients increases. A graph of this (taken from Andrew benchmark report) is available in:
- ![20050131\_graph\_afs\_nfs.jpg](http://www.angelfire.com/hi/plutonic/images/20050131_graph_afs_nfs.jpg)