Determining Resource Requirements

Before proceeding with any installation procedure, you must first ensure that the servers supporting FNS have sufficient memory and disk storage. Space for FNS is in addition to the space needed for your enterprise-level name service (NIS+, NIS, or files).

As a general rule-of-thumb, you will need approximately 17 Kbytes of disk storage for each user and host, plus adequate swap space. Where this disk storage space is located and how it is calculated varies according to your underlying enterprise-level naming service:

• NIS+. The disk storage must be mounted on the machine that will function as the FNS server for the domain or subdomain. In an NIS+ environment, a server hosting the FNS ctx_dir directory does not have to be the same server hosting the standard NIS+ directories, such as org_dir. In order to more evenly distribute server load, many large installations choose to use separate machines for NIS+ and FNS servers. The amount of space needed on an FNS server in an NIS+ environment is determined by the number of users and hosts in the domain, or subdomain, for which the server provides naming.

• NIS. The disk storage must be mounted on the machine that will function as the FNS server for the domain. In an NIS environment, a server hosting FNS does not have to be the same server hosting NIS. In order to more evenly distribute server load, many large installations choose to use separate machines for NIS and FNS servers. The amount of space needed on an FNS server in an NIS environment is determined by the number of users and hosts in the domain.

• Files-based. When your enterprise-level name service is files-based, the amount of disk storage needed by FNS is determined by the number of users and hosts in /etc/users and /etc/hosts files of the machine mounting /var/fn. If every machine has its own /var/fn directory, then the amount of space needed is determined by each machine's user and host files. If /var/fn is mounted on one machine and exported to the rest of the machines on the network by NFS, the space needed by the machine hosting /var/fn is determined by the number of users and hosts in that machine's /etc/users and /etc/hosts files.

For example, to support an FNS environment in an NIS+ domain with 1200 users and hosts, you will need:

• A minimum of 20 Mbytes of disk space beyond the space needed by your underlying enterprise namespace (NIS+, NIS, or files-based).

• An additional 40 Mbytes of swap space.