Networking Requirements

Providing sufficient network bandwidth and availability is the most important configuration for NFS servers. This means that you should configure the appropriate number and type of networks and interfaces.

Follow these tips when setting up and configuring the network.

• Make sure that network traffic is well balanced across all client networks and that networks are not overloaded.

• If one client network is excessively loaded, watch the NFS traffic on that segment.

1. Identify the hosts that are making the largest demands on the servers.

2. Partition the work load or move clients from one segment to another.

Simply adding disks to a system does not improve its NFS performance unless the system is truly disk I/O-bound. The network itself is likely to be the constraint as the file server increases in size, requiring the addition of more network interfaces to keep the system in balance.

Instead of attempting to move more data blocks over a single network, consider characterizing the amount of data consumed by a typical client and balance the NFS reads and writes over multiple networks.

Data-Intensive Applications

Data-intensive applications demand relatively few networks. However, the networks must be of high-bandwidth.

If your configuration has either of the following characteristics, then your applications require high-speed networking:

• Your clients require aggregate data rates of more than 1 Mbyte per second.

• More than one client must be able to simultaneously consume 1 Mbyte per second of network bandwidth.

Configuring the Network When the Primary Application of Your Server Is Data-Intensive

• Configure FDDI, SunATM(TM), or another high-speed network.

If fiber cabling can't be used for logistical reasons, consider FDDI, CDDI, or SunFastEthernet(TM) over twisted-pair implementations. SunATM uses the same size fiber cabling as FDDI. For more information on FDDI, see the FDDI/S3.0 User's Guide.

• Configure one FDDI ring for each five to seven concurrent fully NFS-active clients.

Few data-intensive applications make continuous NFS demands. In typical data-intensive EDA and earth-resources applications, this results in 25-40 clients per ring.

A typical use consists of loading a big block of data that is manipulated then written back to the server. Because the data is written back, these environments can have very high write percentages.

• If your installation has Ethernet cabling, configure one Ethernet for every two active clients.

This almost always requires a SPARCserver 1000, SPARCserver 1000E, SPARCcenter 2000, SPARCcenter 2000E system, or an Ultra Enterprise 3000, 4000, 5000, or 6000 system since useful communities require many networks. Configure a maximum of four to six clients per network.

Attribute-Intensive Applications

In contrast, most attribute-intensive applications are easily handled with less expensive networks. However, attribute-intensive applications require many networks. Use lower-speed networking media, such as Ethernet or Token Ring.

To configure networking when the primary application of the server is attribute-intensive:

• Configure on Ethernet or Token Ring.

• Configure one Ethernet network for eight to ten fully active clients.

More than 20 to 25 clients per Ethernet results in severe degradation when many clients are active. As a check, an Ethernet can sustain about 250-300 NFS ops/second on the SPECnfs_097 (LADDIS) benchmark, albeit at high collision rates. It is unwise to exceed 200 NFS ops/second on a sustained basis.

• Configure one Token Ring network for each ten to fifteen active clients.

If necessary, 50 to 80 total clients per network are feasible on Token Ring networks, due to their superior degradation characteristics under heavy load (compared to Ethernet).

Systems with More Than One Class of Users

Mixing network types is not unreasonable. For example, both FDDI and Token Ring are appropriate for a server that supports both a document imaging application (data-intensive) and a group of PCs running a financial analysis application (most likely attribute-intensive).

The platform you choose is often dictated by the type and number of networks, as they may require many network interface cards.

1. To configure networking for servers that have more than one class of users, mix network types.