This section provides considerations for using the PowerScale SmartConnect load-balancing service. The general IP routing principles are the same with or without SmartConnect.
SmartConnect acts as a DNS delegation server to return IP addresses for SmartConnect zones, generally for load-balancing connections to the cluster. The IP traffic involved is a four-way transaction shown in the following figure:
Figure 8. SmartConnect DNS delegation steps
In the preceding figure, the arrows indicate the following steps:
- Blue arrow (step 1): The client makes a DNS request for sc-zone.domain.com by sending a DNS request packet to the site DNS server.
- Green arrow (step 2): The site DNS server has a delegation record for sc-zone.domain.com and sends a DNS request to the defined nameserver address in the delegation record, the SmartConnect service (SmartConnect Service IP Address).
- Orange arrow (step 3): The cluster node hosting the SmartConnect Service IP (SSIP) for this zone receives the request, calculates the IP address to assign based on the configured connection policy for the pool in question (such as round robin), and sends a DNS response packet to the site DNS server.
- Red arrow (step 4): The site DNS server sends the response back to the client.