Test
This test try to show the maximal number of connections a single NFSv4/ia32/Linux server is able to accept is able to accept. The server export one directory (server:/). The client create a mount point and mount the server export on to the mount point. It repeat the operation as many time as possible until it fails. In this test, client and servers are on the same machine, using the loopback. Time to perform each mount is measured and reported.
Mount operation fails after the 31998 mounts. Error reported is Error 31 : too many links. This limit is caused by the hight number of subdirectories on the client, not by NFS. However linux client and server are able to get 32000 connections/mount
Be aware all connections are done mouting the same exported directory.
This diagram show the time used for each mount. Time is near constant
Conclusion
- A NFSv4/Linux server is able to accept 31998 connections
- Time to perform each mount is near constant
Software configuration
- Server :
- Export options are :
/export *(rw,wdelay,insecure,no_root_squash,no_subtree_check,fsid=0)
- mount options, NFSv4 :
rsize=32768,wsize=32768,timeo=14,intr,noauto
- Linux 2.6.12-rc4-CITI_NFS4_ALL-1
- Distribution : modified Fedora Core 2
hardware configuration
(Client and Server)
- 2 processors : Intel(R)
- Xeon(TM) CPU 2.80GHz, cache 512 KB
- Total memory: 2Gb
- Ethernet: 1Gb/s link
