First some background, VIP stands for Virtual IP address. And for more on HP APA, see a previous post of mine. When installing 10g RAC you need at least a minimum of 3 network interfaces for each node in the RAC cluster.
- A public interface for normal network communications to the node or partition.
- A virtual (public) interface which will be used for failover in case the primary public interface fails. Also used for RAC managment.
- A private interface for the cluster interconnect.
We have 4 software APA NICs (Network Interface Cards) and two regular Gb NICs on each node of the RAC cluster. So, here are our questions:
- How do we use VIP with APA?
- Do they have to be on the same network subnet?
As always, the answer to the first question can be found in a MetaLink document. (296874.1) Configuring the HP-UX Operating System for the Oracle 10g VIP. As stated, there are 2 ways of configuring HP-UX systems for network redundancy to be used for the Virtual IP:
- Oracle VIP with MC/ServiceGuard configured networks only, via multiple physical interfaces on many redundant networks.
- Oracle VIP with APA(i.e. NIC teaming) only via a single logical interface on many redundant networks.
HP Auto Port Aggregation (APA) is a software product that creates link aggregates, often called "trunks," which provide a logical grouping of two or more physical ports into a single "Fat-Pipe". The link aggregates can be active/active(APA aggregate) or active/standby(hot standby mode). An IP is configured only on the single logical interface (usually lan90X), and failure to a single NIC would be transparent to applications that are dependent on a specific interface name.
Auto Port Aggregation(APA) is a NIC teaming solution provided by HP. Although APA is not required when using MC/ServiceGuard (since MC/ServiceGuard has its own network redundancy solution), it is worthwhile to note that a NIC teaming solution can provide highly available VIPs. APA will configure 2 physical NIC's to 1 logical NIC interface. It is usually configured to be lan90x. All that needs to be done for the VIP is to configure it on that 1 logical NIC, similar to what is done on a single NIC configuration.
The answer to the second question is a simple "Yes". The public interface and the virtual interface must both be on the same subnet.
2 comments:
lan900 is usually what the APA is created as and lan900:1 would an IP address that you assign within the APA for use as the VIP.
Here is something you need to know. All of the HP material makes it sound like that creating an APA interface will increase your overall bandwidth. Don't drink the cool-aid. It doesn't. What you really end up with is a single ip address that maps to x number of cards. You still have to submit several jobs to utilize all of the cards. So, the only thing that you gain from APA is better reliability and failover because a single nic failure can be tolerated. That is the bottom line. It doesn't stripe your transfers across all of the links it uses a round-robin approach.
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