In the simplest case, a fileserver houses data and perhaps scripts which can be accessed by any system in an environment. In those cases the software may be installed on, and configured to be run directly from, the file servers. Some software may require quite substantial storage space or might be undergoing rapid (perhaps internal) development. These also may include full copies of the system images from which machines have their operating systems initially installed, or available for repair of any system files that may get corrupted during a machine's lifecycle. Also, in some environments, users might require specialized or occasional access to older versions of software (for instance, developers may need to perform bug fixes and regression testing, or some users may need access to archived data using outdated tools).Ĭommonly, organizations will provide repositories or "depots" of such software, ready for installation as required. Systems may be "imaged" with a minimal or typical cross-section of the most commonly used software. In some computing environments, user workstations and computing nodes do not host installations of the full range of software that users might want to access. This notation generally frees the system manager from having to manage each exported path explicitly via a central automounter map. Where hostname is the host name of the remote machine and nfspath is the path that is exported over NFS on the remote machine. This allows users to access their own files from anywhere in the enterprise, which is extremely useful in UNIX environments, where users may frequently invoke commands on many remote systems via various job-dispatching commands such as ssh, telnet, rsh or rlogin, or via the X11 or VNC protocols.Ī very common default automounter local path is of the form All workstations and other nodes internal to such organizations (typically all those behind a common firewall separating them from the Internet) will be configured with automounter services so that any user logging into any node implicitly triggers access to his or her own home directory which, consequently, is mounted at a common mountpoint, such as /home/ user. Many establishments will have a number of file servers which host the home directories of various users. One can also use automounters to define multiple repositories for read-only data client systems can automatically choose which repository to mount based on availability, file-server load, or proximity on the network. When done properly, users can transparently access files and directories as if all of their workstations and other nodes attach to a single enterprise-wide filesystem. Automounter utilities address these challenges and allow sysadmins to consolidate and centralize the associations of mountpoints (directory names) to the exports. These factors combine to pose challenges to older "static" management methods of filesystem mount tables (the fstab files on Unix systems). Having data mount-points automated makes it easier to reconfigure client systems in such cases. Administrators also often find it necessary to relocate data from one file server to another - to resolve capacity issues and balance the load. Deferring the mounting of such a filesystem until a process actually needs to access it reduces the need to track such mounts, increasing reliability, flexibility and performance.įrequently, one or more fileservers will become inaccessible (down for maintenance, on a remote and temporarily disconnected network, or accessed via a congested link). Usually, only a relatively small number of remote filesystems ( exports) will be active on any given node at any given time. For example, a large to mid-sized organization might have hundreds of file servers and thousands of workstations or other nodes accessing files from any number of those servers at any time. The automounter has the purpose of conserving local system resources and of reducing the coupling between systems which share filesystems with a number of servers. An automounter system utility ( daemon under Unix), when notified of file and directory access attempts under selectively monitored subdirectory trees, dynamically and transparently makes local or remote devices accessible. An automounter is any program or software facility which automatically mounts filesystems in response to access operations by user programs.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |