Hitachi Dynamic Provisioning

Storage Subsystem Administration Guide for Hitachi NAS Platform

Part Number

You can use Hitachi Dynamic Provisioning (HDP) software to improve your storage utilization. The HDP software uses storage-based virtualization layered on top of RAID technology (RAID on RAID) to enable virtual LUNs (dynamically provisioned volumes, DP-Vols) to draw space from multiple pool volumes. This aggregated space widens the storage bottleneck by distributing the I/O to more disks. The greater distribution insulates the server from the realities of the pool volumes (small capacities of individual disks).

HDP with a NAS server provides the following benefits:
  • Improves performance by striping I/O across all available disks
  • Supports larger LUs, up to 64 TiB
  • Reduces the need to use the span-expand command. When HDP thin provisioning is used, an HDP pool can be expanded in small increments any number of times. However, if you expand a storage pool, make the increments as large as the initial size of the storage pool to avoid performance problems.
  • File system creation and expansion are safe, even on thinly provisioned HDP pools, because they check the amount of available space.

If you are using HDP, see the Hitachi NAS Platform HDP Best Practices (MK-92HNAS063) for recommendations.

Note: When using a storage system, there are commonly used Host Mode Options (HMOs) and System Option Modes (SOMs) which should be set correctly. For example, on Hitachi Enterprise RAID systems always enable HMO 7 and 68. When using an HNAS Gateway in a stretched cluster with GAD, enable HMO 78 on the host group containing the HNAS WWPN for the NAS that is considered remote to the system. Contact customer support for more information.