Setting Web management options

The Web Management section lets you restart the cluster and specify refresh rates as observed in monitor mode. The following table describes these configuration settings.

Option

Description

 

 

Restart

Restarts the entire cluster.

 

You must restart the cluster to effect changes you have

 

made to port numbers and virtual IP addresses on the

 

selected node. Restarting the cluster takes about 15

 

seconds, during which time cache and proxy services

 

are disabled.

 

 

Refresh rate in

Specifies the refresh rate for the display of the graphs

Monitor mode

and statistics with which you can monitor the appliance’s

 

performance.

 

 

Setting virtual IP addressing options

The Virtual IP Addressing section lets you define and maintain the appliance’s pool of virtual IP addresses.

The appliance keeps a pool of IP addresses as virtual IP addresses from which to draw and assign IP addresses to nodes as necessary. This practice assures that if a node in the cluster fails, other nodes can assume the failed node’s responsibilities.

What are virtual IP addresses?

Virtual IP addresses are really just IP addresses. They are called virtual addresses because they are not tethered to particular machines and can rotate among nodes in a cluster.

It is common for a single machine to represent multiple IP addresses on the same subnet. This machine would have a primary or real IP address bound to its interface card and would also serve many more virtual addresses.

Using virtual IP addressing for node failover

You can set up your user base to use a DNS round-robin pointing at virtual IP addresses, as opposed to using the real IP addresses of the appliance machines in the cluster.

Because virtual IP addresses are not bound to machines, a cluster can steal addresses from inactive nodes and distribute those addresses among the remaining live nodes.

Using a proprietary management protocol, appliance nodes communicate their status with their peers. If a node fails, its peers notice the failure and quickly negotiate which of the remaining nodes will mask the fault by taking over the failed node’s virtual interface.

26Intel NetStructure Cache Appliance Administrator’s Guide

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Intel 1520 manual Setting Web management options, Setting virtual IP addressing options, What are virtual IP addresses?