Disk quota

Limit set by a system administrator restricting some file system usage Example of qgroup (quota group) of a Btrfs filesystem A disk quota is a limit set by a system administrator that restricts certain aspects of file system usage on modern operating systems. The function of using disk quotas is to allocate limited disk space in a reasonable way. Types of quotas There are two basic types of disk quotas. The first, known as a usage quota or block quota, limits the amount of disk space that can be used. The second, known as a file quota or inode quota, limits the number of files and directories that can be created. In addition, administrators usually define a warning level, or soft quota, at which users are informed they are nearing their limit, that is less than the effective limit, or hard quota. There may also be a small grace interval, which allows users to temporarily violate their quotas by certain amounts if necessary. Quotas Disk quotas are typically implemented on a per-user or per-group basis. That is, a system administrator defines a usage or file quota specific to a certain user or group. In some filesystems (e.g. ext4, XFS, f2fs, ZFS, Lustre) it is also possible to defin