The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.
A Network File System (NFS) server can share directory hierarchies in its local file systems with remote client systems over an IP-based network. After an NFS server exports a directory, NFS clients mount this directory if they have been granted permission to do so. The directory appears to the client systems as if it were a local directory. NFS centralizes storage provisioning and can improves data consistency and reliability.
Oracle Linux supports three versions of the NFS protocol:
NFSv2 and NFSv3 rely on Remote Procedure Call (RPC) services,
which are controlled by the rpcbind service.
rpcbind responds to requests for an RPC service
and sets up connections for the requested service. In addition,
separate lockd and rpc.statd
services are used to handle locking and mounting protocols.
Configuring a firewall to cope with the various ranges of ports
that are used by all these services is complex and error prone.
NFSv4 does not use rpcbind as the NFS server
itself listens on TCP port 2049 for service requests. The mounting
and locking protocols are also integrated into the NFSv4 protocol,
so the lockd and rpc.statd
services are also not required. These refinements mean that
firewall configuration for NFSv4 is no more difficult than for a
service such as HTTP.
The following table describes the various services that are used with versions 2, 3, and 4 of NFS:
Service | Used in Version | Description |
|---|---|---|
| 2 and 3 | Handles the RPC processes that allow NFS clients to obtain locks on files on the server.
Started by the |
| 2, 3, and 4 | Starts all services that are required to implement shared NFS file systems. If only NFSv4 clients can access the server, this is the only NFS service that needs to be started explicitly. |
| 2, 3, and 4 | Implements the kernel-space part of the NFS service.
Started by the |
| 2 and 3 | Starts the RPC processes that allow NFS clients to lock files on the server.
Start this service after the |
| 2 and 3 | Responds to requests for an RPC service and sets up connections for the requested service.
Start this service before the
For more information, see the
|
| 2,3, and 4 |
Implement the RPCSEC_GSS protocol, which provides
authentication only (
Started by the
For more information, see the
|
| 4 |
Provides mapping between NFSv4 names (strings of the
form
Started by the
For more information, see the
|
| 2,3, and 4 | Handles mount requests from NFSv2 and NFSv3 clients by checking that the NFS server exports the requested NFS share and that the client is allowed to access it. For NFSv4, this service is required only to set up exports.
Started by the
For more information, see the
|
| 2,3, and 4 |
Implements the user-space part of the NFS service, which
specifies on what sort of sockets the kernel service
should listen, what NFS versions it supports, and how
many kernel threads it should use. The number of threads
is visible and settable via
Started by the
For more information, see the
|
| 2,3, and 4 | Provides quota information for the quota command to display user quotas for remote file systems and the edquota command to set quotas on remote file systems.
Started by the
For more information, see the
|
| 2 and 3 | Implements the Network Status Monitor (NSM) RPC protocol, which notifies NFS clients when an NFS server has restarted after an uncontrolled shutdown or system crash.
Started by the
For more information, see the
|