Dell PS Series Architecture Load Balancers Owners Manual
Summary
Technical white paper describing the load balancing architecture in Dell Storage PS Series (EqualLogic) SAN environments. Explains the automatic load balancing mechanisms that distribute I/O across storage pool members, including volume rebalancing, thin-provisioned space reclamation, and pool-level optimization. Covers the different types of load balancers, their operational triggers, configuration options, and monitoring capabilities. Details how the PS Series SAN automatically redistributes data and workload across pool members to maintain optimal performance. Intended for storage administrators and solution architects designing and managing Dell EqualLogic storage area networks.
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Dell Storage PS Series Architecture: Load Balancers Dell EMC Engineering February 2017
A Dell EMC Technical White Paper
Page Summary Contents For Dell PS Series Architecture Load Balancers Owners Manual
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Dell Storage PS Series Architecture: Load Balancers Dell EMC Engineering February 2017 A Dell EMC Technical White Paper
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Revisions Date Description August 2011 Initial release February 2017 Updated to reflect new branding and formatting Acknowledgements This paper was produced by the following members of the Dell EMC™ S...
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Table of contents 1 Introduction ................................................................................................................................................................... 5 2...
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Executive summary This document provides VMware® and Dell™ PS Series storage administrators with recommended best practices when configuring a virtual environment. It describes the function of PS Seri...
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1 Introduction In many organizations, significant effort is devoted to tuning resources: modifying network settings on switches, changing various parameters on servers, re-configuring Qo S on the WAN,...
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2 PS Series overview Dell PS Series storage is an award-winning, virtualized, scale-out SAN architecture that provides simplified management, ease of use, a comprehensive set of data protection and re...
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3 Why automatically balance SAN resources The IT resources available to most organizations are limited. The realities of budgets, staffing, knowledge, and the business needs of the organization are of...
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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 refe...
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5 How the Network Load Balancer (NLB) works Communications between application servers (i SCSI initiators) and volumes (i SCSI targets) are called connections. A PS Series Group will present all i SCS...
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6 How the Capacity Load Balancer (CLB) works The CLB ensures that as volumes are created and deleted, and as members are added to and removed from a pool, the relative percent of capacity in use is ma...
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other members in the pool. An FSTP will cancel other RBPs. Once the low space issue that prompted the FSTP has been resolved, the CLB will create new RBPs if they are required.2 All data movement, reg...
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7 How the Automatic Performance Load Balancer (APLB) works The APLB feature is designed to help alleviate the difficulties inherent in manually balancing the utilization of SAN performance resources. ...
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Example of APLB in a non-tiered environment The APLB is surprisingly simple in its concept and execution, leveraging various aspects of the PS Series architecture to automatically balance the performa...
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which is a composite score of factors such as RAID type, disk speed, number of disks, as well as PS Series controller type and the current I/O load. The member with the lower relative busy-ness will b...
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Reduction of worst-case-scenario purchasing: By working continually, the APLB can detect and act on cyclical business processes, such as increased end-of-month activity by the finance group enabling t...
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8 Observing latencies and high I/O data Various metrics central to the APLB behavior (such as array latencies and breakdown of data classified as high, medium, and low I/O) are displayed using SAN Hea...
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9 Tiering with the APLB When provided with tiered resources in a pool, such as arrays with different spindle speeds or set to different RAID types, the APLB is able to use them to tier the workload. T...
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10 Using the APLB with hybrid arrays The PS Series hybrid arrays (such as the PS4210XS, PS6210XS, and PS6610ES) use their own internal implementation of the APLB to compensate for unbalanced or tiered...
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Example of APLB in a tiered environment 19 Dell Storage PS Series Architecture: Load Balancers | TR1070
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11 Scenarios in which APLB action is limited There are several cases when the APLB will not take action. First, if all of the members of the storage pool are exhibiting low latencies, then the resourc...
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Fourth, if a customer has chosen to override the automatic placement of volumes by the capacity balancer by using the CLI bind command, all balancing of any sort is disabled for that volume. Note that...
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12 APLB and backup operations Backup operations place a large burden on storage resources but should not be a problem for the APLB. Backup operations largely result in sequential reads, and only acces...
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13 Disabling the APLB While not recommended, the APLB may be disabled by unchecking the Enable Performance Balancing in Pools checkbox in the GUI. Note that this is a Group-wide setting and will affec...
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14 Summary The various load balancers that work in a PS Series pool provide a very flexible, dynamic framework that is able to quickly adapt the PS Series storage to the shifting requirements of the c...
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A Additional examples of APLB The following are some additional examples of the data distribution before and after APLB has performed its load balancing function. Rebalancing after adding capacity-opt...
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Rebalancing after adding performance-optimized resources to a pool 26 Dell Storage PS Series Architecture: Load Balancers | TR1070
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Rebalancing with multiple hybrid arrays 27 Dell Storage PS Series Architecture: Load Balancers | TR1070
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B Technical support and resources Dell.com/Support is focused on meeting customer needs with proven services and support. Dell Tech Center is an online technical community where IT professionals have ...
Manual Details
| Brand | Dell |
|---|---|
| Pages | 28 |
| File Size | 1.02 MB |
| Published | June 25, 2026 |
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Frequently Asked Questions
What are the types of load balancers in PS Series?
The PS Series system includes three types: Network Load Balancer (NLB), Capacity Load Balancer (CLB), and Automatic Performance Load Balancer (APLB).
How does the Capacity Load Balancer (CLB) work?
The CLB distributes data across the available capacity resources in a storage pool to ensure balanced storage utilization.
How does the Automatic Performance Load Balancer (APLB) work?
The APLB monitors latency and high I/O data to move virtual machines to resources that offer optimal performance.
What is the purpose of the Network Load Balancer (NLB)?
The NLB actively manages data on storage members to adapt in a fluid manner and maintain optimal resource utilization.