Thin Provisioning; Figure 23 Storage Capacity Virtualization - Fujitsu ETERNUS AF250 Design Manual

1. Function
Operations Optimization (Deduplication/Compression and Storage Virtualization)

Thin Provisioning

The Thin Provisioning function has the following features:
Storage Capacity Virtualization
•
The physical storage capacity can be reduced by allocating the virtual drives to a server, which allows efficient
use of the storage capacity. The volumes more than the capacity of all the installed drives can be allocated by
setting the capacity required for virtual volumes in the future.
• TPV Balancing
I/O access to the virtual volume can be distributed among the RAID groups in a pool, by relocating and balanc-
ing the physical allocation status of the virtual volume.
TPV/FTV Capacity Optimization (Zero Reclamation)
•
Data in physically allocated areas are checked in blocks and unnecessary areas (areas where 0 is allocated to
all of the data in each block) are released to unallocated areas.
Storage Capacity Virtualization
Thin Provisioning improves the usability of the drives by managing the physical drives in a pool, and sharing the
unused capacity among the virtual volumes in the pool. The volume capacity that is seen from the server is vir-
tualized to allow the server to recognize a larger capacity than the physical volume capacity. Because a large
capacity virtual volume can be defined, the drives can be used in a more efficient and flexible manner.
Initial cost can be reduced because less drive capacity is required even if the capacity requirements cannot be
estimated. The power consumption requirements can also be reduced because a fewer number of drives are in-
stalled.

Figure 23 Storage Capacity Virtualization

Management server
In the Thin Provisioning function, the RAID group, which is configured with multiple drives, is managed as a Thin
Provisioning Pool (TPP). When a Write request is issued, a physical area is allocated to the virtual volume. The
free space in the TPP is shared among the virtual volumes which belong to the TPP, and a virtual volume, which
is larger than the drive capacity in the ETERNUS AF, can be created. A virtual volume to be created in a TPP is
referred to as a Thin Provisioning Volume (TPV).
Thin Provisioning Pool (TPP)
•
A TPP is a physical drive pool which is configured with one or more RAID groups. TPP capacity can be expanded
in the units of RAID groups. Add RAID groups with the same specifications (RAID level, drive type, and number
of member drives) as those of the existing RAID groups.
Virtual volume
Write
Mapping
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays Design Guide (Basic)
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Data that is
actually used
Allocated
Allocated as required
46
Physical drives
RAID group
P3AG-1822-09ENZ0