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Storage Foundation for Oracle® RAC 7.4.1 Administrator's Guide - Linux

Last Published: 2019-10-17

Product(s): InfoScale & Storage Foundation (7.4.1)

Platform: Linux

Section I. SF Oracle RAC concepts and administration
1. Overview of Storage Foundation for Oracle RAC
2. Administering SF Oracle RAC and its components
Section II. Performance and troubleshooting
Section III. Reference
1. Appendix A. List of SF Oracle RAC health checks
2. Appendix B. Error messages

Adding and removing LLT links

In an SF Oracle RAC cluster, Oracle Clusterware heartbeat link must be configured as an LLT link. If Oracle Clusterware and LLT use different links for their communication, then the membership change between VCS and Oracle Clusterware is not coordinated correctly. For example, if only the Oracle Clusterware links are down, Oracle Clusterware kills one set of nodes after the expiry of the css-misscount interval and initiates the Oracle Clusterware and database recovery, even before CVM and CFS detect the node failures. This uncoordinated recovery may cause data corruption.

If you need additional capacity for Oracle communication on your private interconnects, you can add LLT links. The network IDs of the interfaces connected to the same physical network must match. The interfaces specified in the PrivNIC or MultiPrivNIC configuration must be exactly the same in name and total number as those which have been used for LLT configuration.

You can use the lltconfig command to add or remove LLT links when LLT is running.

LLT links can be added or removed while clients are connected.

See the lltconfig(1M) manual page for more details.

Note:

When you add or remove LLT links, you need not shut down GAB or the high availability daemon, had. Your changes take effect immediately, but are lost on the next restart. For changes to persist, you must also update the /etc/llttab file.

To add LLT links

Depending on the LLT link type, run the following command to add an LLT link:

For ether link type:

# lltconfig -t devtag -d device 
[-b ether ] [-s SAP] [-m mtu]  [-I] [-Q]

For UDP link type:

# lltconfig -t devtag -d device 
-b udp [-s port] [-m mtu]
-I IPaddr -B bcast

For UDP6 link type:

# lltconfig -t devtag -d device 
-b udp6 [-s port] [-m mtu]
-I IPaddr [-B mcast]

For RDMA link type:

# lltconfig -t devtag -d device
 -b rdma -s port [-m mtu]
 -I IPaddr -B bcast

Where:

devtag	Tag to identify the link
device	Device name of the interface. For link type ether, you can specify the device name as an interface name. For example, eth0. Preferably, specify the device name as eth-macaddress. For example, eth- xx:xx:xx:xx:xx:xx. For link types udp and udp6, the device is the udp and udp6 device name respectively. For link type rdma, the device name is udp.
bcast	Broadcast address for the link type udp and rdma
mcast	Multicast address for the link type udp6
IPaddr	IP address for link types udp, udp6 and rdma
SAP	SAP to bind on the network links for link type ether
port	Port for link types udp, udp6 and rdma
mtu	Maximum transmission unit to send packets on network links

For example:

For ether link type:

# lltconfig -t eth4 -d eth4 -s 0xcafe -m 1500

For UDP link type:

# lltconfig -t link1 -d udp -b udp -s 50010
-I 192.168.1.1 -B 192.168.1.255

For UDP6 link type:

# lltconfig -t link1 -d udp6 -b udp6 -s 50010 -I 2000::1

For RDMA link:

# lltconfig -t link1 -d udp -b rdma -s 50010
 -I 192.168.1.1 -B 192.168.1.255

Note:

If you want the addition of LLT links to be persistent after reboot, then you must edit the /etc/lltab with LLT entries.

To remove an LLT link

If the link you want to remove is configured as a PrivNIC or MultiPrivNIC resource, you need to modify the resource configuration before removing the link.
If you have configured the link under PrivNIC or MultiPrivNIC as a failover target in the case of link failure, modify the PrivNIC or MultiPrivNIC configuration as follows:
```
# haconf -makerw
# hares -modify resource_name Device link_name \
device_id [-sys hostname]
# haconf -dump -makero
```
For example, if the links eth1, eth2, and eth3 were configured as PrivNIC resources, and you want to remove eth3:
```
# haconf -makerw
# hares -modify ora_priv Device eth1
			0  eth2 	1
```
where eth1 and eth2 are the links that you want to retain in your cluster.
```
# haconf -dump -makero
```
Run the following command to disable a network link that is configured under LLT.
```
# lltconfig -t devtag -L disable
```
Wait for the 16 seconds (LLT peerinact time).
Run the following command to remove the link.
```
# lltconfig -u devtag
```