Figure 1-1. Direct-Attached, Single-Cluster Configuration
public network
cluster node | | cluster node |
| | | | private network |
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Fibre Channel connections
Fibre Channel connections
storage system
EMC® PowerPath® Limitations in a Direct-Attached Cluster
EMC PowerPath provides failover capabilities and multiple path detection as well as dynamic load balancing between multiple ports on the same storage processor. However, direct-attached clusters supported by Dell connect to a single port on each storage processor in the storage system. Because of the single port limitation, PowerPath can provide only failover protection, not load balancing, in a direct-attached configuration.
SAN-Attached Cluster
In a SAN-attached cluster, all of the nodes are attached to a single storage system or to multiple storage systems through a SAN using redundant switch fabrics. SAN-attached clusters are superior to direct-attached clusters in configuration flexibility, expandability, and performance.
Figure 1-2 shows a SAN-attached cluster.
