Dell Unity: What are factors to Consider when Adding Backend Expansion Card to Dell Unity Array
Summary: What are factors to Consider when Adding Backend Expansion Card to Dell Unity Array?
This article applies to
This article does not apply to
This article is not tied to any specific product.
Not all product versions are identified in this article.
Symptoms
Dell Unity 500 and 600 Hybrid arrays have functionality to add extra backend Busses.
When and what factors should a customer consider before adding an extra Backend expansion card to a Dell Unity array?
Cause
Dell Unity arrays have two onboard 12 Gb/s SAS ports per SP on each DPE that are configured for two backend busses. An additional 4-port I/O module can be Provisioned on Dell Unity 500 and 600 hybrid systems to create extra back End Busses. Each SAS port runs at 12 Gb/s Compared to (Vnx2 series 6 Gb/s). There are four lanes per port so each port can do approx. 25 Gb/s (2.5 GB/sec) and with four embedded ports per array Total Bandwidth on backend ports per array is 100 Gb/s.
Resolution
In General, the four onboard I/O SAS ports per array provide Adequate IOPS and bandwidth for Most workloads. The Extra SAS I/O module card should only be considered.
- For arrays with Bandwidth that exceeds 10GB/s.
- Arrays with more than 19 DAE's Configured.
- Arrays with more than 500 drives configured
Note: Configuring I/O module card as backend ports reduces the number of I/O Modules available for your frontend host connections. This must be fully considered as your frontend ports could become a future bottleneck in large configurations.
Extra Backend ports on large configurations with Data services like Snapshots /deduplication and compression may increase CPU utilization.
Extra Backend ports on large configurations with Data services like Snapshots /deduplication and compression may increase CPU utilization.
Additional Information
Dell Unity Family
Dell Unity 500 /600 Hybrid Arrays
Affected Products
Dell EMC Unity HybridProducts
Dell EMC Unity Family, Dell EMC Unity HybridArticle Properties
Article Number: 000052531
Article Type: Solution
Last Modified: 19 May 2025
Version: 5
Find answers to your questions from other Dell users
Support Services
Check if your device is covered by Support Services.