4 Configuring Networks for Oracle Grid Infrastructure and Oracle RAC

Check that you have the networking hardware and internet protocol (IP) addresses required for an Oracle Grid Infrastructure for a cluster installation.

Note:

For the most up-to-date information about supported network protocols and hardware for Oracle RAC installations, refer to the Certify pages on the My Oracle Support website. See "Checking Hardware and Software Certification on My Oracle Support" for instructions.

4.1 Network Interface Hardware Requirements

Review these requirements to ensure that you have the minimum network hardware technology for Oracle Grid Infrastructure clusters.

4.1.1 Network Requirements for Each Node

Verify that servers where you install Oracle Grid Infrastructure meet the minimum network requirements for installation.

  • The host name of each node must use only the characters a-z, A-Z, 0-9, and the dash or minus sign (-). Host names using underscores (_) are not supported.

  • Each node must have at least two network adapters or network interface cards (NICs): one for the public network interface, and one for the private network interface, or the interconnect. Each network adapter has a network connection name.

    Note:

    Do not use the names PUBLIC and PRIVATE (all caps) for the public or private (interconnect) network connection names.

  • Network adapters must be at least 1 GbE, with 10 GbE recommended.

  • If you plan to use Oracle ASM running in a different cluster for storage, then you must either have a third network adapter for accessing the ASM network, or use the same network adapter that is used for the private network interface.

4.1.2 Network Requirements for the Private Network

The following is a list of requirements for the private network configuration:

  • The private network connection names must be different from the network connection names used for the public network.

  • Each node's private interface for interconnects must be on the same subnet.

    For example, if the private interfaces have a subnet mask of 255.255.255.0, then your private network is in the range 192.168.0.0--192.168.0.255, and your private addresses must be in the range of 192.168.0.[0-255]. If the private interfaces have a subnet mask of 255.255.0.0, then your private addresses can be in the range of 192.168.[0-255].[0-255]

  • The private network connection name cannot contain any multibyte language characters. The private network connection names are case-sensitive.

  • Both IPv4 and IPv6 addresses are supported.

  • If you use OUI to install Oracle Grid Infrastructure, then the private network connection names associated with the private network adapters must be the same on all nodes.

    For example, if you have a two-node cluster, and PrivNIC is the private network connection name for node1, then PrivNIC must be the private network connection name for node2.

  • For the private network, the network adapters must use high-speed network adapters and switches that support TCP/IP (minimum requirement is 1 Gigabit Ethernet, 10GbE recommended). Alternatively, use InfiniBand for the interconnect.

    Note:

    TCP is the interconnect protocol for Oracle Clusterware. You must use a switch for the interconnect. Oracle recommends that you use a dedicated switch.

    Oracle does not support token-rings or crossover cables for the interconnect.

  • For the private network adapters, the endpoints of all designated network connection names must be completely reachable on the network. There should be no node that is not connected to every other node on the private network. You can test if an interconnect interface is reachable using ping.

4.1.3 Network Requirements for the Public Network

The following is a list of requirements for the public network configuration:

  • The public network connection names must be different from the private network connection names.

  • Public network connection names are case-sensitive.

  • The public network connection name cannot contain any multibyte language characters.

  • If you use OUI to install Oracle Grid Infrastructure, then the public network connection names associated with the public network adapters for each network must be the same on all nodes.

    For example, if you have a two-node cluster, you cannot configure network adapters on node1 with NIC1 as the public network connection name and on node2 have NIC2 as the public network connection name. Public network connection names must be the same, so you must configure NIC1 as the public network connection name on both nodes.

  • For the public network, each network adapter must support transmission control protocol and internet protocol (TCP/IP).

  • The network adapters must use high-speed network adapters and switches that support TCP/IP (minimum requirement is 1 Gigabit Ethernet, 10GbE recommended).

4.1.4 IPv6 Protocol Support for Windows

Oracle Grid Infrastructure and Oracle RAC support the standard IPv6 address notations specified by RFC 2732 and global and site-local IPv6 addresses as defined by RFC 4193.

Cluster member node interfaces can be configured to use IPv4, IPv6, or both types of Internet protocol addresses. However, be aware of the following:

  • Configuring public VIPs: During installation, you can configure VIPs for a given public network as IPv4 or IPv6 types of addresses. You can configure an IPv6 cluster by selecting VIP and SCAN names that resolve to addresses in an IPv6 subnet for the cluster, and selecting that subnet as public during installation. After installation, you can also configure cluster member nodes with a mixture of IPv4 and IPv6 addresses.

    If you install using static virtual IP (VIP) addresses in an IPv4 cluster, then the VIP names you supply during installation should resolve only to IPv4 addresses. If you install using static IPv6 addresses, then the VIP names you supply during installation should resolve only to IPv6 addresses.

    During installation, you cannot configure the cluster with VIP and SCAN names that resolve to both IPv4 and IPv6 addresses. For example, you cannot configure VIPs and SCANS on some cluster member nodes to resolve to IPv4 addresses, and VIPs and SCANs on other cluster member nodes to resolve to IPv6 addresses. Oracle does not support this configuration.

  • Configuring private IP interfaces (interconnects): You must configure the private network as an IPv4 network. IPv6 addresses are not supported for the interconnect.

  • Redundant network interfaces: If you configure redundant network interfaces for a public or VIP node name, then configure both interfaces of a redundant pair to the same address protocol. Also ensure that private IP interfaces use the same IP protocol. Oracle does not support names using redundant interface configurations with mixed IP protocols. You must configure both network interfaces of a redundant pair with the same IP protocol.

  • GNS or Multi-cluster addresses: Oracle Grid Infrastructure supports IPv4 DHCP addresses, and IPv6 addresses configured with the Stateless Address Autoconfiguration protocol, as described in RFC 2462.

Note:

Link-local and site-local IPv6 addresses as defined in RFC 1884 are not supported

See Also:

4.1.5 Using Multiple Public Network Adapters

You can configure multiple network adapters for the public network interface.

Oracle recommends that you do not identify multiple public network connection names during Oracle Grid Infrastructure installation.

  1. Use a third-party technology for your platform to aggregate the multiple public network adapters before you start installation.
  2. During installation, select the single network connection name for the combined network adapters as the public interface.

If you configure two network adapters as public network adapters in the cluster without using an aggregation technology, the failure of one public network adapter on a node does not result in automatic VIP failover to the other public network adapter.

4.1.6 Network Configuration Tasks for Windows Server Deployments

Microsoft Windows Server has many unique networking features. Some of these features require special configuration to enable Oracle software to run correctly on Windows Server.

  • Disabling Windows Media Sensing
    Windows Media Sensing must be disabled for the private network adapters.
  • Setting the Bind Order for Network Adapters
    In Windows Networking Properties, the public network connection on each node must be listed first in the bind order (the order in which network services access the node). The private network connection should be listed second.
  • Deconfigure DNS Registration for Public Network Adapter
    To prevent Windows Server 2008 from potentially registering the wrong IP addresses for the node in DNS after a server restart, you must deconfigure the "Register this connection's addresses in DNS" option for the public network adapters.
  • Manually Configure Automatic Metric Values
    Automatic Metric feature automatically configures the metric for the local routes that are based on link speed. To prevent OUI from selecting the wrong network interface during installation, you must customize the metric values for the public and private network interfaces.
  • Set the TCP/IP Dynamic Port Range for Oracle RAC Installations
    For certain configurations of Oracle RAC in high load environments it is possible for the system to exhaust the available number of sockets. To avoid this problem, expand the dynamic port range for TCP/IP.
  • Verify Privileges for Copying Files in the Cluster
    During installation, OUI copies the software from the local node to the remote nodes in the cluster. The installation user must have privileges on the other nodes in the cluster to copy the files.

4.1.6.1 Disabling Windows Media Sensing

Windows Media Sensing must be disabled for the private network adapters.

To disable Windows Media Sensing for TCP/IP, you must set the value of the DisableDHCPMediaSense parameter to 1 on each node. Because you must modify the Windows registry to disable Media Sensing, you should first backup the registry and confirm that you can restore it, using the methods described in your Windows documentation.
  1. Backup the Windows registry.
  2. Use Registry Editor to view the following key in the registry: 
    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
  3. Add a new DWORD value to the Parameters subkey: 
    Value Name: DisableDHCPMediaSense
Value: 1
  4. Exit the Registry Editor and restart the computer.
  5. Repeat steps 1 through 4 on each node in your cluster.

4.1.6.2 Setting the Bind Order for Network Adapters

In Windows Networking Properties, the public network connection on each node must be listed first in the bind order (the order in which network services access the node). The private network connection should be listed second.

The names used for each class of network adapter (such as public) must be consistent across all nodes. You can use nondefault names for the network adapter, for example, PublicLAN, if the same names are used for the same class of network adapters on each node in the network.
  1. Right click My Network Places and choose Properties.
  2. In the Advanced menu, click Advanced Settings.
  3. If the public network connection name is not the first name listed under the Adapters and Bindings tab, then select it and click the arrow to move it to the top of the list.
  4. Click OK to save the settings and then exit the network setup dialog.

4.1.6.3 Deconfigure DNS Registration for Public Network Adapter

To prevent Windows Server 2008 from potentially registering the wrong IP addresses for the node in DNS after a server restart, you must deconfigure the "Register this connection's addresses in DNS" option for the public network adapters.

Due to a change in functionality in the Windows Server 2008 operating system, the DNS client service registers all of the network connections of a computer in DNS. In earlier versions of Windows Server, the DNS client service registered only the primary, or first, network adapter IP address in DNS.
  1. Start the Windows Server Manager application.
  2. Select View Network Connections.
  3. Right-click the network adapter that provides the Public network interface and select Properties.
  4. Select the Networking tab, and then select Internet Protocol Version 4 (TCP/IPv4).

    Note:

    If you configure this setting in IPv4, then Windows automatically configures the same setting for IPv6
  5. Click Properties.
  6. On the General tab, click Advanced.
  7. Select the DNS tab.
  8. Deselect Register this connection's addresses in DNS.

See Also:

"Best Practices Analyzer for Domain Name System: Configuration" on Microsoft Technet, specifically http://technet.microsoft.com/en-us/library/ff807401(v=ws.10).aspx

4.1.6.4 Manually Configure Automatic Metric Values

Automatic Metric feature automatically configures the metric for the local routes that are based on link speed. To prevent OUI from selecting the wrong network interface during installation, you must customize the metric values for the public and private network interfaces.

The Automatic Metric feature is enabled by default, and it can also be manually configured to assign a specific metric. The public and private network interface for IPv4 use the Automatic Metric feature of Windows. When the Automatic Metric feature is enabled and using the default values, it can sometimes cause OUI to select the private network interface as the default public host name for the server when installing Oracle Grid Infrastructure.
  1. In Control Panel, double-click Network Connections.
  2. Right-click a network interface, and then click Properties.
  3. Click Internet Protocol (TCP/IP), and then click Properties.
  4. On the General tab, click Advanced.
  5. To specify a metric, on the IP Settings tab, click to clear the Automatic metric check box.
  6. In the Interface Metric field, set the public network interface metric to a lower value than the private network interface.
    For example, you might set the public network interface metric to 100 and the private network interface metric to 300.

4.1.6.5 Set the TCP/IP Dynamic Port Range for Oracle RAC Installations

For certain configurations of Oracle RAC in high load environments it is possible for the system to exhaust the available number of sockets. To avoid this problem, expand the dynamic port range for TCP/IP.

  1. Open a command line window as an Administrator user.
  2. Run the following command: 
    netsh int ipv4 set dynamicport tcp start=20000 num=40000

4.1.6.6 Verify Privileges for Copying Files in the Cluster

During installation, OUI copies the software from the local node to the remote nodes in the cluster. The installation user must have privileges on the other nodes in the cluster to copy the files.

  1. Verify that you have Administrator privileges on the other nodes in the cluster by running the following command on each node, where nodename is the name of the remote node: 
    net use \\nodename\C$
  2. After installation, if your system does not use the net share shown in the above example, then you can remove the unused net share using the following command: 
    net use \\nodename\C$ /delete

4.1.7 Network Interface Configuration Options for Performance

The precise configuration you choose for your network depends on the size and use of the cluster you want to configure, and the level of availability you require.

If you access Oracle ASM remotely, or a certified Network-attached Storage (NAS) is used for Oracle RAC and this storage is connected through Ethernet-based networks, then you must have a third network interface for data communications. Failing to provide three separate network interfaces in this case can cause performance and stability problems under heavy system loads.

4.2 Oracle Grid Infrastructure IP Name and Address Requirements

The Oracle Grid Naming Service (GNS) is used with large clusters to ease network administration cost.

For small clusters, you can use a static configuration of IP addresses. For large clusters, manually maintaining the large number of required IP addresses becomes too cumbersome.

4.2.1 About Oracle Grid Infrastructure Name Resolution Options

Before starting the installation, you must have at least two interfaces configured on each node: One for the private IP address and one for the public IP address.

You can configure IP addresses for Oracle Grid Infrastructure and Oracle RAC with one of the following options:

  • Dynamic IP address assignment using Multi-cluster or standard Oracle Grid Naming Service (GNS). If you select this option, then network administrators delegate a subdomain to be resolved by GNS (standard or multicluster). Requirements for GNS are different depending on whether you choose to configure GNS with zone delegation (resolution of a ___domain delegated to GNS), or without zone delegation (a GNS virtual IP address without ___domain delegation).

  • For GNS with zone delegation:

    • For IPv4, a DHCP service running on the public network the cluster uses

    • For IPv6, an autoconfiguration service running on the public network the cluster uses

    • Enough DHCP addresses to provide 1 IP address for each node, and 3 IP addresses for the cluster used by the Single Client Access Name (SCAN) for the cluster

  • Use an existing GNS configuration. Starting with Oracle Grid Infrastructure 12c Release 1 (12.1), a single GNS instance can be used by multiple clusters. To use GNS for multiple clusters, the DNS administrator must have delegated a zone for use by GNS. Also, there must be an instance of GNS started somewhere on the network and the GNS instance must be accessible (not blocked by a firewall). All of the node names registered with the GNS instance must be unique.

  • Static IP address assignment using DNS or host file resolution. If you select this option, then network administrators assign a fixed IP address for each physical host name in the cluster and for IPs for the Oracle Clusterware managed VIPs. In addition, ___domain name system (DNS)-based static name resolution is used for each node, or host files for both the clusters and clients have to be updated, and SCAN functionality is limited. Selecting this option requires that you request network administration updates when you modify the cluster.

Note:

  • Oracle recommends that you use a static host name for all non-VIP server node public host names.

  • Public IP addresses and virtual IP addresses must be in the same subnet.

  • Oracle only supports DHCP-assigned networks for the default network, not for any subsequent networks.

For clusters using single interfaces for private networks, each node's private interface for interconnects must be on the same subnet, and that subnet must connect to every node of the cluster. For example, if the private interfaces have a subnet mask of 255.255.255.0, then your private network is in the range 192.168.0.0--192.168.0.255, and your private addresses must be in the range of 192.168.0.[0-255]. If the private interfaces have a subnet mask of 255.255.0.0, then your private addresses can be in the range of 192.168.[0-255].[0-255].

4.2.2 Cluster Name and SCAN Requirements

During installation, you are prompted to confirm the default Single Client Access Name (SCAN), which is used to connect to databases within the cluster irrespective of which nodes the database instances run on. If you change the SCAN from the default, then the name that you use must be globally unique throughout your enterprise.

The cluster name must be unique across your enterprise, must be at least one character long and no more than 15 characters in length, must be alphanumeric, cannot begin with a numeral, and may contain hyphens (-). Underscore characters (_) are not allowed.

If you configure a Standard cluster, and choose a Typical install, then the SCAN is also the name of the cluster. In that case, the SCAN must meet the requirements for a cluster name. The SCAN can be no longer than 15 characters.

In an Advanced installation, the SCAN and cluster name are entered in separate fields during installation, so cluster name requirements do not apply to the name used for the SCAN. The SCAN can be longer than 15 characters. If you enter a ___domain with the SCAN name, and you want to use GNS with zone delegation, then the ___domain must be the GNS ___domain.

Caution:

Select your name carefully. After installation, you can only change the cluster name by reinstalling Oracle Grid Infrastructure.

4.2.3 IP Name and Address Requirements For Grid Naming Service (GNS)

The network administration must configure the ___domain name server (DNS) to delegate resolution requests for cluster names (any names in the subdomain delegated to the cluster) to the GNS.

If you enable Grid Naming Service (GNS), then name resolution requests to the cluster are delegated to the GNS, which listens on the GNS VIP address. When a request comes to the ___domain, GNS processes the requests and responds with the appropriate addresses for the name requested. To use GNS, you must specify a static IP address for the GNS VIP address.

Note:

You cannot use GNS with another multicast DNS. To use GNS, disable any third-party mDNS daemons on your system.

Related Topics

4.2.4 IP Name and Address Requirements For Multi-Cluster GNS

Review the following requirements for using Multi-cluster GNS:

  • About Multi-Cluster GNS Networks
    The general requirements for Multi-cluster GNS are similar to those for standard GNS. Multi-cluster GNS differs from standard GNS in that Multi-cluster GNS provides a single networking service across a set of clusters, rather than a networking service for a single cluster.
  • Configuring GNS Server Clusters
    Review these requirements to configure GNS server clusters.
  • Configuring GNS Client Clusters
    Review these requirements to configure GNS client clusters.
  • Creating and Using a GNS Client Data File
    Generate a GNS client data file and copy the file to the GNS client cluster member node on which you are running the Oracle Grid Infrastructure installation.

4.2.4.1 About Multi-Cluster GNS Networks

The general requirements for Multi-cluster GNS are similar to those for standard GNS. Multi-cluster GNS differs from standard GNS in that Multi-cluster GNS provides a single networking service across a set of clusters, rather than a networking service for a single cluster.

To provide networking service, Multi-cluster GNS is configured using DHCP addresses, and name advertisement and resolution is carried out with the following components:

  • The GNS Server cluster performs address resolution for GNS Client clusters. A GNS Server cluster is the cluster where Multi-cluster GNS runs, and where name resolution takes place for the subdomain delegated to the set of clusters.

  • GNS Client clusters receive address resolution from the GNS Server cluster. A GNS Client cluster is a cluster that advertises its cluster member node names using the GNS Server cluster.

4.2.4.2 Configuring GNS Server Clusters

Review these requirements to configure GNS server clusters.

To use this option, your network administrators must have delegated a subdomain to GNS for resolution.
  1. Before installation, create a static IP address for the GNS VIP address.
  2. Provide a subdomain that your DNS servers delegate to that static GNS IP address for resolution.

4.2.4.3 Configuring GNS Client Clusters

Review these requirements to configure GNS client clusters.

  • To configure a GNS Client cluster, check to ensure all of the following requirements are completed:

    • A GNS Server instance must be running on your network, and it must be accessible (for example, not blocked by a firewall)

    • All of the node names in the GNS ___domain must be unique; address ranges and cluster names must be unique for both GNS Server and GNS Client clusters.

    • You must have a GNS Client data file that you generated on the GNS Server cluster, so that the GNS Client cluster has the information needed to delegate its name resolution to the GNS Server cluster, and you must have copied that file to the GNS Client cluster member node on which you run the Oracle Grid Infrastructure installation.

4.2.4.4 Creating and Using a GNS Client Data File

Generate a GNS client data file and copy the file to the GNS client cluster member node on which you are running the Oracle Grid Infrastructure installation.

  1. On a GNS Server cluster member, run the following command, where path_to_file is the name and path ___location of the GNS Client data file you create: 
    srvctl export gns -clientdata path_to_file -role {client | secondary}

    For example:

    C:\> srvctl export gns -clientdata C:\Users\grid\gns_client_data -role client
  2. Copy the GNS Client data file to a secure path on the GNS Client node where you run the GNS Client cluster installation.
    The Oracle Installation user must have permissions to access that file. Oracle recommends that no other user is granted permissions to access the GNS Client data file.
  3. During installation, you are prompted to provide a path to that file.
  4. After you have completed the GNS Client cluster installation, you must run the following command on one of the GNS Server cluster members to start GNS service, where path_to_file is the name and path ___location of the GNS Client data file: 
    srvctl add gns -clientdata path_to_file

    For example:

    C:\> srvctl add gns -clientdata C:\Users\grid\gns_client_data

See Also:

Oracle Clusterware Administration and Deployment Guide for more information about GNS Server and GNS Client administration

4.2.5 IP Address Requirements for Manual Configuration

If you do not enable GNS, then the public and VIP addresses for each node must be static IP addresses. Public, VIP and SCAN addresses must be on the same subnet.

IP addresses on the subnet you identify as private are assigned as private IP addresses for cluster member nodes. Oracle Clusterware manages private IP addresses in the private subnet. You do not have to configure these addresses manually in a hosts file.

The cluster must have the following addresses configured:

  • A public IP address for each node configured before installation, and resolvable to that node before installation

  • A VIP address for each node configured before installation, but not currently in use

  • Three static IP addresses configured on the ___domain name server (DNS) before installation so that the three IP addresses are associated with the name provided as the SCAN, and all three addresses are returned in random order by the DNS to the requestor. These addresses must be configured before installation in the DNS to resolve to addresses that are not currently in use. The SCAN name must meet the requirements specified in "Cluster Name and SCAN Requirements"

  • A private IP address for each node configured before installation, but on a separate, private network, with its own subnet. The IP address should not be resolvable except by other cluster member nodes.

  • A set of one or more networks over which Oracle ASM serves its clients. The ASM network does not have to be a physical network; it can be a virtual network. The ASM network must use either a third NIC, or share a private network adapter. The NIC can be a virtual NIC.

Note:

Oracle strongly recommends that you do not configure SCAN VIP addresses in the hosts file. Use DNS resolution for SCAN VIPs. If you use the hosts file to resolve SCANs, then you will only be able to resolve to one IP address and you will have only one SCAN address.

Configuring SCANs in a DNS or a hosts file is the only supported configuration. Configuring SCANs in a Network Information Service (NIS) is not supported.

Related Topics

4.2.6 Confirming the DNS Configuration for SCAN

You can use the nslookup command to confirm that the DNS is correctly associating the SCAN with the addresses.

After installation, when a client sends a request to the cluster, the Oracle Clusterware SCAN listeners redirect client requests to servers in the cluster.
  • At a command prompt, use the nslookup command and specify the name of the SCAN for your cluster.
    For example: 
    C:\> nslookup mycluster-scan
Server:         dns3.example.com
Address:        192.0.2.001
 
Name:   mycluster-scan.example.com
Address: 192.0.2.201
Name:   mycluster-scan.example.com
Address: 192.0.2.202
Name:   mycluster-scan.example.com
Address: 192.0.2.203

4.2.7 Grid Naming Service for a Traditional Cluster Configuration Example

To use GNS, you must specify a static IP address for the GNS VIP address, and you must have a subdomain configured on your ___domain name servers (DNS) to delegate resolution for that subdomain to the static GNS IP address.

To use GNS, you must specify a static IP address for the GNS VIP address, and you must have a subdomain configured on your DNS to delegate resolution for that subdomain to the static GNS IP address.

As nodes are added to the cluster, your organization's DHCP server can provide addresses for these nodes dynamically. These addresses are then registered automatically in GNS, and GNS provides resolution within the subdomain to cluster node addresses registered with GNS.

Because allocation and configuration of addresses is performed automatically with GNS, no further configuration is required. Oracle Clusterware provides dynamic network configuration as nodes are added to or removed from the cluster. The following example is provided only for information.

With IPv6 networks, the IPv6 auto configuration feature assigns IP addresses and no DHCP server is required.

Assuming a two node cluster where you have defined the GNS VIP, after installation you might have a configuration similar to that shown in the following table. In this configuration, the cluster name is mycluster, the GNS parent ___domain is gns.example.com, the subdomain is cluster01.example.com, the 192.0.2 portion of the IP addresses represents the cluster public IP address subdomain, and 192.168.0 represents the private IP address subdomain.

Table 4-1 Example of a Grid Naming Service Network Configuration

Identity Home Node Host Node Given Name Type Address Address Assigned By Resolved By

GNS VIP

None

Selected by Oracle Clusterware

mycluster-gns-vip.example.com

Virtual

192.0.2.1

Fixed by network administrator

DNS

Node 1 Public

Node 1

node1

node1Foot 1Footref 1

Public

192.0.2.101

Fixed

GNS

Node 1 VIP

Node 1

Selected by Oracle Clusterware

node1-vip

Virtual

192.0.2.104

DHCP

GNS

Node 1 Private

Node 1

node1

node1-priv

Private

192.168.0.1

Fixed or DHCP

GNS

Node 2 Public

Node 2

node2

node2Footref 1

Public

192.0.2.102

Fixed

GNS

Node 2 VIP

Node 2

Selected by Oracle Clusterware

node2-vip

Virtual

192.0.2.105

DHCP

GNS

Node 2 Private

Node 2

node2

node2-priv

Private

192.168.0.2

Fixed or DHCP

GNS

SCAN VIP 1

none

Selected by Oracle Clusterware

mycluster-scan.cluster01.example.com

Virtual

192.0.2.201

DHCP

GNS

SCAN VIP 2

none

Selected by Oracle Clusterware

mycluster-scan.cluster01.example.com

Virtual

192.0.2.202

DHCP

GNS

SCAN VIP 3

none

Selected by Oracle Clusterware

mycluster-scan.cluster01.example.com

Virtual

192.0.2.203

DHCP

GNS

Footnote 1 Node host names may resolve to multiple addresses, including VIP addresses currently running on that host.

4.2.8 Domain Delegation to Grid Naming Service

If you are configuring Grid Naming Service (GNS) for a standard cluster, then before installing Oracle Grid Infrastructure you must configure DNS to send to GNS any name resolution requests for the subdomain served by GNS.

The subdomain that GNS serves represents the cluster member nodes.

4.2.8.1 Choosing a Subdomain Name for Use with Grid Naming Service

To implement GNS, your network administrator must configure the DNS to set up a ___domain for the cluster, and delegate resolution of that ___domain to the GNS VIP. You can use a separate ___domain, or you can create a subdomain of an existing ___domain for the cluster.

The subdomain name, can be any supported DNS name such as sales-cluster.rac.com.

Oracle recommends that the subdomain name be distinct from your corporate ___domain. For example, if your corporate ___domain is mycorp.example.com, the subdomain for GNS might be rac-gns.com.

If the subdomain is not distinct, then it should be for the exclusive use of GNS. For example, if you delegate the subdomain mydomain.example.com to GNS, then there should be no other domains that share it such as lab1.mydomain.example.com.

See Also:

4.2.8.2 Configuring DNS for Domain Delegation to Grid Naming Service

You must configure the DNS to send GNS name resolution requests using DNS forwarders.

If the DNS server is running on a Windows server that you administer, then the following steps must be performed to configure DNS:
  1. Click Start, then select Programs. Select Administrative Tools and then click DNS manager.
    The DNS server configuration wizard starts automatically.
  2. Use the wizard to create an entry for the GNS virtual IP address, where the address is a valid DNS name.
    For example, if the cluster name is mycluster, and the ___domain name is example.com, and the IP address is 192.0.2.1, you could create an entry similar to the following: 
    mycluster-gns-vip.example.com: 192.0.2.1

    The address you provide must be routable.

    Note:

    The ___domain name may not contain underscores. Windows may allow the use of underscore characters, but this practice violates the Internet Engineering Task Force RFC 952 standard and is not supported by Oracle.
  3. To configure DNS forwarders, click Start, select Administrative Tools, and then select DNS.
  4. Right-click ServerName, where ServerName is the name of the server, and then click the Forwarders tab.
  5. Click New, then type the name of the DNS ___domain for which you want to forward queries in the DNS ___domain box, for example, clusterdomain.example.com. Click OK.
  6. In the selected ___domain's forwarder IP address box, type the GNS VIP address, and then click Add.
  7. Click OK to exit.
If the DNS server is running on a different operating system, then refer to the Oracle Grid Infrastructure Installation Guide for that platform, or your operating system documentation.

Note:

Experienced DNS administrators may want to create a reverse lookup zone to enable resolution of reverse lookups. A reverse lookup resolves an IP address to a host name with a Pointer Resource (PTR) record. If you have reverse DNS zones configured, then you can automatically create associated reverse records when you create your original forward record.

4.2.9 Manual IP Address Configuration Example

If you choose not to use GNS, then before installation you must configure public, virtual, and private IP addresses. Also, check that the default gateway can be accessed by a ping command.

To find the default gateway, use the ipconfig command, as described in your operating system's help utility.

For example, with a two node cluster where the cluster name is mycluster, and each node has one public and one private interface, and you have defined a SCAN ___domain address to resolve on your DNS to one of three IP addresses, you might have the configuration shown in the following table for your network interfaces.

Table 4-2 Manual Network Configuration Example

Identity Home Node Host Node Given Name Type Address Address Assigned By Resolved By

Node 1 Public

Node 1

node1

node1Foot 2Footref 2

Public

192.0.2.101

Fixed

DNS

Node 1 VIP

Node 1

Selected by Oracle Clusterware

node1-vip

Virtual

192.0.2.104

Fixed

DNS, hosts file

Node 1 Private

Node 1

node1

node1-priv

Private

192.168.0.1

Fixed

DNS, hosts file, or none

Node 2 Public

Node 2

node2

node2Footref 2

Public

192.0.2.102

Fixed

DNS

Node 2 VIP

Node 2

Selected by Oracle Clusterware

node2-vip

Virtual

192.0.2.105

Fixed

DNS, hosts file

Node 2 Private

Node 2

node2

node2-priv

Private

192.168.0.2

Fixed

DNS, hosts file, or none

SCAN VIP 1

none

Selected by Oracle Clusterware

mycluster-scan

Virtual

192.0.2.201

Fixed

DNS

SCAN VIP 2

none

Selected by Oracle Clusterware

mycluster-scan

Virtual

192.0.2.202

Fixed

DNS

SCAN VIP 3

none

Selected by Oracle Clusterware

mycluster-scan

Virtual

192.0.2.203

Fixed

DNS

Footnote 2 Node host names may resolve to multiple addresses.

You do not have to provide a private name for the interconnect. If you want name resolution for the interconnect, then you can configure private IP names in the system hosts file or DNS. However, Oracle Clusterware assigns interconnect addresses on the interface defined during installation as the private interface (Local Area Connection 2, for example), and to the subnet used for the private subnet.

The addresses to which the SCAN resolves are assigned by Oracle Clusterware, so they are not fixed to a particular node. To enable VIP failover, the configuration shown in the previous table defines the SCAN addresses and the public and VIP addresses of both nodes on the same subnet, 192.0.2.

Note:

All host names must conform to the Internet Engineering Task Force RFC 952 standard, which permits alphanumeric characters. Host names using underscores ("_") are not allowed.

4.3 Intended Use of Network Adapters

During installation, you are asked to identify the planned use for each network adapter (or network interface) that Oracle Universal Installer (OUI) detects on your cluster node.

Each NIC performs only one of the following roles:

  • Public

  • Private

  • Do Not Use

You must use the same private adapters for both Oracle Clusterware and Oracle RAC. The precise configuration you choose for your network depends on the size and use of the cluster you want to configure, and the level of availability you require. Network interfaces must be at least 1 GbE, with 10 GbE recommended.

For network adapters that you plan to use for other purposes–for example, an adapter dedicated to a non-Oracle network file system–you must identify those network adapters as "do not use" adapters so that Oracle Clusterware ignores them.

If certified Network-attached Storage (NAS) is used for Oracle RAC and this storage is connected through Ethernet-based networks, then you must have a third network interface for NAS I/O. Failing to provide three separate interfaces in this case can cause performance and stability problems under load.

4.4 Broadcast Requirements for Networks Used by Oracle Grid Infrastructure

Broadcast communications address resolution protocol (ARP) must work properly across all the public and private interfaces configured for use by Oracle Grid Infrastructure.

The broadcast communications must work across any configured virtual local area networks (VLANs) that the public or private network interfaces uses.

4.5 Multicast Requirements for Networks Used by Oracle Grid Infrastructure

On each cluster member node the Oracle multicast DNS (mDNS) daemon uses multicasting on all network interfaces to communicate with other nodes in the cluster.

Multicasting is required on the private interconnect. For this reason, at a minimum, you must enable multicasting for the cluster for the following:

  • Across the broadcast ___domain as defined for the private interconnect

  • On the IP address subnet ranges 224.0.0.0/24 and 230.0.1.0/24

You do not need to enable multicast communications across routers.