Considerations when using HDP pools

Storage Subsystem Administration Guide for Hitachi NAS Platform

Part Number

Consider the following when using the HDP pools:

As with storage pools based on parity groups:
  • Deleting a file system is not always permanent. Sometimes file systems are recoverable from the recycle bin by issuing the filesystem-undelete command.
  • Recycling a file system is permanent.
Unlike storage pools based on parity groups, on HDP-based storage pools:
  • Freed chunks move to the vacated-chunks list, which is stored in Cod.
  • Vacated chunks are reused when you create or expand file systems in the same storage pool.
  • By reusing the same chunks, the server avoids exhausting space prematurely. Reusing chunks from recycled file systems allows the server to avoid wasting real disk space on deleted data. Instead, the server reallocates chunks from recycled file systems to other file systems.