White Papers

8 Dell Storage PS Series Architecture: Load Balancers | TR1070
4 PS Series load balancers in PS Series storage pools
When you initialize the first array and create a PS Series Group, a default pool is automatically established.
An array added to the Group is referred to as a member of the Group. The first member added to the Group
is initially placed into the default pool, and administrators subsequently deploy volumes from this pool. Within
the pool, resources such as network bandwidth, disk capacity, and I/O are balanced automatically. Multiple
pools can be created to isolate volumes and separate members. This may be done for a variety of reasons,
including technical (placing specific application data on resources such as SSD) or business reasons
(ensuring that legal department data is isolated from the data from other departments).
With more than one pool, administrators can initiate moving volumes or members between the pools
seamlessly, with no downtime to the applications. Within a pool, PS Series arrays are designed to automate
the placement of data to maximize the utilization of the resources that the customer has chosen for their SAN.
There are three load balancers that operate within a pool:
 The NLB (Network Load Balancer) manages the assignment of individual iSCSI connections to
Ethernet ports on the pool members
 The CLB (Capacity Load Balancer) manages the utilization of the disk capacity in the pool
 The APLB (Automatic Performance Load Balancer) manages the distribution of high I/O data within
the pool.