Increasing the size of a file system

File Service Administration Guide for Hitachi NAS Platform

Version
14.9.x
Audience
anonymous
Part Number
MK-92HNAS006-31

There are two methods to expand the amount of storage allocated to a file system:

  • Manual expansion

    Manually expanding a file system allows you to add storage capacity to a file system (or a tier of a tiered file system) immediately. You specify the new size of a file system, and the storage is allocated immediately. The maximum size that a file system or tier can attain is specified, and the file system size can be set to the maximum size supported by the storage pool in which the file system was created.

  • Automatic expansion

    File system auto-expansion allows a file system to grow to by adding chunks of storage on an as-needed basis, as long as the confinement limit or the maximum file system size has not been reached. For tiered file systems, auto-expansion can be applied independently to one or to all tiers of the file system, allowing one tier to expand independently of another.

    When auto-expansion is enabled, and the file system (or tier) reaches approximately 80 percent of its allocated capacity, one or more additional chunks are allocated (refer to the Storage Subsystem Administration Guide for a discussion of chunks). The maximum size that a file system can attain can be specified, or the file system size can be allowed to grow to the maximum size supported by the storage pool in which the file system was created.

Note: Once storage is allocated to a file system, that storage becomes dedicated to that file system, meaning that once a file system is expanded, its size may not be reduced. Unused space in the file system cannot be reclaimed, allocated to another file system, or removed. To reclaim the storage space, the file system must be relocated to different storage or deleted.

Increasing the amount of storage allocated to a file system (manually or automatically) does not require that the file system be taken offline.