How much space can the clients use?

This topic describes how to plan for controlling the amount of space the clients can use in the global namespace by defining fileset quotas.

When creating a fileset, you can specify a maximum size for the fileset, called a quota, and specify whether SAN File System should generate an alert if the size of the fileset reaches or exceeds a specified percentage of the maximum size, called a threshold. For example, if the quota on the fileset is set to 100 GB, and the threshold is 80%, and alert will be generated when the fileset contains 80 GB of data. (Note that the quota is based on space allocated to the fileset, not the data is contains.)

The action taken when the fileset reaches its quota size depends on whether the quota is defined as hard or soft. If a hard quota is used, once the threshold is reached, new client requests to add more space to the fileset (by creating or extending files) are denied. If a soft quota is used, which is the default, more space can be allocated but alerts continue to be sent. Once the amount of physical storage available to global fileset is exceeded, no more space can be used. The quota limit, threshold and quota type can be set individually for each fileset.

Note:
  • The space used by a fileset includes the space used by FlashCopy® images. It does not include the space used by any filesets nested within it.
  • The metadata servers compute and track hard quota limits for filesets in multiples of the partition size. If a hard quota is not set as a multiple of the partition size, quota violation errors appear in the log file even though the size of the fileset has not reached the specified limit. To avoid this problem, specify hard quota limits as multiples of the partition size (for example, if the partition size is 16 MB, set the quota to multiples of 16).

Parent topic: Planning the global namespace configuration

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