Dell SC4020 Deployment Manual page 51

Fault Domains in Legacy Mode
Each pair of primary and reserved ports is grouped into a fault domain in the Storage Center software.
The fault domain determines which ports are allowed to fail over to each other.
The following requirements apply to fault domains in legacy mode on a Storage Center:
• A fault domain must contain one type of transport media (FC or iSCSI, but not both).
• A fault domain must contain one primary port and one reserved port.
• The reserved port must be on a different storage controller than the primary port.
Requirements for Legacy Mode
The following requirements must be met to configure a storage system in legacy mode.
Table 3. Legacy Mode Requirements
Requirement
Storage controller front-
end ports
Multipathing
Fibre Channel zoning
Related links
Fibre Channel Zoning
Example Legacy Mode Configuration
The following figure shows a Storage Center in legacy mode that is connected to switches and servers.
• Fault domain 1 (shown in orange) is comprised of primary port P1 on storage controller 1 and reserved
port R1 on storage controller 2.
• Fault domain 2 (shown in blue) is comprised of primary port P2 on storage controller 2 and reserved
port R2 on storage controller 1.
• Fault domain 3 (shown in gray) is comprised of primary port P3 on storage controller 1 and reserved
port R3 on storage controller 2.
• Fault domain 4 (shown in red) is comprised of primary port P4 on storage controller 2 and reserved
port R4 on storage controller 1.
Connect the Front-End Cabling
Description
On an SC4020 with FC front-end ports, each storage controller must have
two FC front-end ports to connect two paths to each Fibre Channel fabric.
On an SC4020 with iSCSI front-end ports, each storage controller must have
two iSCSI front-end ports to connect two paths to each Ethernet network.
If multiple active paths are available to a server, the server must be configured
for MPIO to use more than one path simultaneously.
Fibre Channel switches must be zoned to meet the legacy mode zoning
requirements.
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