Peer Storage Operations; Groups; Pools - Dell PS4000 Configuration Manual

3 Peer Storage Operations

3.1 Groups

A PS Series SAN Group is a Storage Area Network (SAN) comprised of one or more PS Series arrays
connected to an IP network. Each array in a group is called a group member. Each member is assigned
to a storage pool. There can be up to 4 pools within the group.
A group can consist of up to 16 arrays of any family or model as long as all arrays in the group are
running firmware with the same major and minor release number. For example, it is supported to have
different arrays in the same group running different maintenance release levels, as long as their major
and minor revision levels match. An example of this would be running version 4.0.1 and 4.0.3 on
different arrays in the same group. An example of an unsupported configuration would be different
arrays in the same group running 4.0.1 and 4.1.0 (the minor versions differ). The only exception to this
rule is for short term time periods when array firmware versions may be out of sync while upgrading
the firmware on each array within a group. Features available for use within the group are determined
by the lowest version of FW running within the group.
Note: It is recommended that all arrays run the exact same version of FW at all times,
except during a FW upgrade process. (See Section 2.3.4 on page 7 for more information.)

3.2 Pools

A pool is a container that each member is assigned after being added to the group. A pool can have
between 1 to 8 members. There is always at least one pool in any group and it is called the ―default
pool‖ unless the name is changed. Regardless of the name of this pool, it is always considered the
default storage pool. All newly added members are automatically assigned to the default pool. The
default pool cannot be deleted.
Pools can be used as part of an overall tiered storage strategy for the SAN. Tiered storage is storage
that is differentiated and optimized for the type of applications and data being hosted. Instead of
optimizing all of the storage in the group for maximum storage utilization, a tiered storage system
allows for the administrator to optimize different arrays for a variety of requirements such as
application performance requirements or cost efficiency.
Pools are the containers that provide scope for all automated storage optimization features of the
group. Pools with multiple arrays can implement different RAID policies within the pool. The
EqualLogic automated optimization features will automatically move a volume from an array or set of
arrays with one RAID policy to another array or set of arrays with a different RAID policy if it is
determined that the application needs more (or less) performance.
The following rules apply to pools:

Each member can be assigned to only one pool.

Each pool can host up to 8 members.

Each group will have at least 1 pool – the default pool.
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