Requirements
| Chapter 1. Installation Overview |

## Requirements

You must comply with the following requirements to install AFS successfully.

### Login Identity

Log into the machine you are installing as the local superuser root. When instructed, also authenticate to AFS using Kerberos as the administrative user admin.

### General Requirements

- You must have a Kerberos 5 realm running for your site, and the ability to create new principals within that realm. If you are working with an existing cell using the deprecated kaserver or Kerberos v4 authentication, please see kaserver and legacy Kerberos 4 authentication for modifications to the following instructions.

- You must have a NTP, or similar, timeservice running. Each AFS machine should derive its system time from this timeservice. If you are working with an existing cell, and wish to use AFS's internal time service, please see Appendix B for modifications to the following instructions.

- You must have an OpenAFS Binary Distribution for each system type you are installing, or have built a binary from the supplied source code. Unless otherwise noted, the Binary Distribution includes software for both client and server machines.

- All AFS machines that belong to a cell must be able to access each other via the network.

- The machine must be running the standard, vendor-supplied version of the operating system supported by the current version of AFS. The operating system must already be installed on the machine's root partition.

- You must be familiar with the current operating system and disk configuration of the machine you are installing.

- All hardware and non-AFS software on the machine must be functioning normally.

- No critical processes can be running on the machine you are installing, because you may need to reboot it during the installation.

### File Server Machine Requirements

- Cell configuration is simplest if the first machine you install has the lowest IP address of any database server machine you currently plan to install. If you later configure a machine with a lower IP address as a database server machine, you must update the /usr/vice/etc/CellServDB file on all of your cell's client machines before the installation. For further discussion, see Installing Database Server Functionality.

- The partition mounted on the /usr directory must have a sufficient amount of space to hold the AFS binaries that will be used; a few hundred MB should be more than sufficient.

  More significant amounts of space on the partition are required by the administrative databases stored in the /usr/afs/db directory and the server process log files stored in the /usr/afs/logs directory. The exact requirement depends on many factors, such as the size of your cell and how often you truncate the log files.

- There should be at least one partition (or logical volume, if the operating system and AFS support them) dedicated exclusively to storing AFS volumes. Special configuration is required to use non-dedicated partitions as the backing store for AFS file data. The total number and size of server partitions on all file server machines in the cell determines how much space is available for AFS files.

### Client Machine Requirements

- The partition mounted on the /usr directory must have a sufficient amount of disk space to store the AFS binaries that will be used; a few hundred MB should be more than sufficient.

- On a client machine that uses a disk cache, there must be enough free space on the cache partition (by convention, mounted on the /usr/vice/cache directory) to accommodate the cache. The minimum recommended cache size is 50 MB, but larger caches generally perform better. It is recommended to have a dedicated partition for this cache, as the client does not degrade gracefully when the partition containing the cache is filled by other processes.

- On a client machine that uses a memory cache, there must be at least 50 MB of machine memory to devote to caching, but again more memory generally leads to better performance. For further discussion, see the sections in Installing Additional Client Machines about configuring the cache.

Recommended Reading List |  | Supported System Types