Enabling quotas

The GPFS™ quota system can help you control file system usage.

Quotas can be defined for individual users, groups of users, or filesets. Quotas can be set on the total number of files and the total amount of data space consumed. When setting quota limits for a file system, the system administrator should consider the replication factors of the file system. Quota management takes replication into account when reporting on and determining if quota limits have been exceeded for both block and file usage. In a file system that has either data replication or metadata replication set to a value of two, the values reported on by both the mmlsquota and mmrepquota commands are double the value reported by the ls command.

Whether or not to enable quotas when a file system is mounted may be specified at file system creation by using the -Q option on the mmcrfs command or changed at a later time by using the -Q option on the mmchfs command. After the file system has been mounted, quota values are established by issuing the mmedquota command and activated by issuing the mmquotaon command. The default is to not have quotas activated.

GPFS levels are defined at three limits that you can explicitly set using the mmedquota and mmdefedquota commands:

Soft limit: Defines levels of disk space and files below which the user, group of users, or fileset can safely operate.
Specified in units of kilobytes (k or K), megabytes (m or M), or gigabytes (g or G). If no suffix is provided, the number is assumed to be in bytes.
Hard limit: Defines the maximum amount of disk space and number of files the user, group of users, or fileset can accumulate.
Specified in units of kilobytes (k or K), megabytes (m or M), or gigabytes (g or G). If no suffix is provided, the number is assumed to be in bytes.
Grace period: Allows the user, group of users, or fileset to exceed the soft limit for a specified period of time. The default period is one week. If usage is not reduced to a level below the soft limit during that time, the quota system interprets the soft limit as the hard limit and no further allocation is allowed. The user, group of users, or fileset can reset this condition by reducing usage enough to fall below the soft limit; or the administrator can increase the quota levels using the mmedquota or mmdefedquota.

For implications of quotas for different protocols, see Implications of quotas for different protocols in IBM Spectrum Scale: Administration and Programming Reference.