1. NFS

2. Network File System What is NFS?
The Network File System is a file system that may be accessed via a network connection.
The Network File System (NFS) was developed to allow machines to mount a disk partition on a remote machine as if it were on a local hard drive.

3. Cont…
This allows for fast, seamless sharing of files across a network .
With other file systems, the storage device must be directly attached to the local system.
However, with NFS this is not a requirement, making possible a variety of different configurations, from centralized file system servers, to entirely diskless computer systems

4. Cont… 1. Means server keeps no state:
NFS developed by Sun Microsystems
Native method for file sharing between
Unix/Linux systems
Stateless protocol:
1. Means server keeps no state:
2. Renders server crashes `easily recoverable‘

5. Cont… Systems are clients, servers or both
Clients import shared file systems
Servers export shared file systems
Servers easy to implement via network daemons
Clients require kernel modifications
Linux systems normally work as both already
NFS is NOT Unix/Linux specific (e.g. PCNFS)

6. Exporting System
Exporting handled by daemons .nfsd and Must be running for NFS export to work
Exported file systems listed in /etc/exports, format is:
hostname(flags) [hostname(flags)]
Important flags:
(read only)
(read/write)

7. Cont… _squash (map all uid/gid to something)
(specify user ID to map to)
(specify group ID to map to)
After changing /etc/exports, restart NFS
killall -HUP rpc.nfsd
killall -HUP mount

8. Viewing exports ● Use showmount: $ showmount -e
$ showmount -e hostname
Export list for
landlord.gbdirect.co.uk:
/usr/local/gbdirect/cvsroot
roti.gbdirect.co.uk
/home/adamg
/home/andylong

9. Cont… Mount a remotely exported directory $ mount
hostname:/share name /local/directory
If successful, the export named /share name on host is mounted on our mount point /local/directory

10. Cont… just as if local, Remote host must be exporting the directory
You must have access permission
Your local mount point must exist
Exactly like mounting a device