Fileservers

Some machines make use of fileservers. A fileserver is a computer that lets other machines use its disks. In the UNIX world we usually say it exports its disks. Other computers can mount these disks in the same way as they might mount a local hard disk, CDROM or USB memory stick.

Fileservers are very useful and often used to store people's home directories. Several computers can use the same fileserver to ensure that all of a user's files are available regardless of which computer they are logged into. If the fileserver let a user fill up all of the shared disk space it would prevent anyone from writing to the disk. This is generally regarded as A Bad Idea and so Linux allows a fileserver to only allow users to use a certain amount of disk space each. These are called quotas.

You can see what your quota is and how much you are using with the quota -v command.

pjh1003@tcmpc55:~> quota -v
Filesystem  blocks   quota   limit   grace  files  quota  limit  grace
 /dev/sda8 2291368* 2097152 2306867   4days   4565      0      0

Disks mounted remotely use the `network filesystem', or NFS, and although useful using a disk like this is very slow. If you are running a program that writes a lot of output you should always try to write the output to a local disk, and then copy it to the NFS disk if needs be.