HP XP P9500 Storage - Manual (Page 17)

Thin provisioning includes:
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“Thin Provisioning concepts ” (page 17)
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“Thin Provisioning” (page 19)
Thin Provisioning
Though basic or traditional provisioning strategies can be appropriate and useful in specific
scenarios, they can be expensive to set up, awkward and time consuming to configure, difficult to
monitor, and error prone when maintaining storage.
Although Thin Provisioning requires some additional steps, it is a simpler alternative to the traditional
provisioning methods. It uses thin provisioning technology that allows you to allocate virtual storage
capacity based on anticipated future capacity needs, using virtual volumes instead of physical disk
capacity.
Overall storage use rates may improve because you can potentially provide more virtual capacity
to applications while using fewer physical disks. It provides lower initial cost, greater efficiency,
and storage management freedom for storage administrators. In this way, Thin Provisioning software:
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Simplifies storage management
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Self-balances resource use and optimizes performance
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Maximizes physical disk usage
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Reduces device address requirements over traditional provisioning.
Thin Provisioning concepts
Thin Provisioning is a volume management feature that allows storage managers and System
Administrators to efficiently plan and allocate storage to users or applications. It provides a platform
for the array to dynamically manage data and physical capacity without frequent manual
involvement.
Thin Provisioning provides three important capabilities: thin provisioning of storage, enhanced
volume performance, and larger volume sizes.
Thin Provisioning is more efficient than traditional provisioning strategies. It is implemented by
creating one or more Thin Provisioning pools (THP pools) of physical storage space using multiple
LDEVs. Then, you can establish virtual THP volumes (THP V-VOLs) and connect them to the individual
THP pools. In this way, capacity to support data can be randomly assigned on demand.
THP V-VOLs are of a user-specified logical size without any corresponding physical space. Actual
physical space (in 42-MB pool page units) is automatically assigned to a THP V-VOL from the
connected THP pool as that volume’s logical space is written to over time. A new volume does not
have any pool pages assigned to it. The pages are loaned out from its connected pool to that THP
volume until the volume is reformatted or deleted. At that point, all of that volume’s assigned pages
are returned to the pool’s free page list. This handling of logical and physical capacity is called
thin provisioning. In many cases, logical capacity will exceed physical capacity.
Thin Provisioning enhances volume performance. This is an automatic result of how THP V-VOLs
map capacity from individual THP pools. A pool is created using from one to 1024 LDEVs (pool
volumes) of physical space. Each pool volume is sectioned into 42-MB pages. Each page is
consecutively laid down on a number of RAID stripes from one pool volume. The pool’s 42-MB
pool pages are assigned on demand by any of a THP V-VOLs that are connected to that pool.
Other pages assigned over time to that THP V-VOL randomly originate from the next free page
from some other pool volume in the pool.
THP V-VOL are defined as 3390-A. 3390-A volumes can be defined as larger volumes than
traditional volumes. The volume type was created to reduce device address requirements.
Setting up a Thin Provisioning environment requires a few extra steps. You still configure various
array groups to a desired RAID level, and then create one or more 3390-V volumes (LDEVs) on
Thin provisioning 17