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This article mainly explains "What are Oracle cluster terms and parameters?" The explanation in this article is simple and clear, easy to learn and understand. Please follow the ideas of Xiaobian slowly and deeply to study and learn "What are Oracle cluster terms and parameters?"

1. VF ( Voting File)

This file is used to store disk heartbeat information for each node, as well as a list of nodes that each node can see, which is used to determine the status of the node during brain splitting and whether the node should continue to survive or leave the cluster.

In addition, the following sections of VF also hold important information:

1 . Lease Block: This information exists only in clusters with version 11gR2 and above. Starting with version 11.2, the number of each node is no longer fixed. All valid node numbers are stored in VF lease blocks. When a node joins a cluster, it needs to renew the node number used before leasing from the lease block. The reason Oracle does this is to make clustering more flexible. The lease procedure for the node number can be found in ocssd.log of ocssd.bin startup procedure.

2 . kill block: This section is mainly used to store poison packages, that is, information that requires the node to restart.

When a node in the cluster asks another node to leave the cluster (e.g., brain split), it writes poisonpackage in the kill block of VF, and when the target node reads VF, it finds poisonpackage and restarts itself. This is also a basic concept that the author has been emphasizing many times-one node in the cluster can only ask another node to restart, but the real restart node is the local node itself.

2. Oracle Cluster Registry (OCR)

For IOgR2 and llgRI versions of clusters, OCR is used to record all information related to the cluster, such as cluster name, VF location, public and private network configuration, etc. Therefore, OCR is important in this version. For the 11gR2 version of the cluster, OCR becomes less important and is mainly used to record resource information related to CRSD. Of course, regardless of which version, OCR's data structure remains unchanged, still tree hierarchical.

3. misscount

This value is used to define the timeout period for the cluster network heartbeat. The default value is 30s. That is, when one or more nodes in the cluster continuously lose network heartbeats for more than the miscount time, the cluster needs to be reconfigured and one or more nodes need to leave the cluster. Of course, for the 11gR2 version of the cluster, this value is also the timeout for node local heartbeats, since local heartbeats and network heartbeats are sent by the same thread.

4. LIOT ( longνo timeout)

This parameter defines the I/O timeout period for VF when the node performs disk heartbeat. The default value is 200s. That is to say, if CSSD fails to complete disk heartbeat on a VF for 200s continuously, the VF will be offline.

5. SIOT ( short 1/0 timeout)

This parameter defines the I/O timeout for VF when the node is reconfigured. The default value is miscount (30)reboottime(3)=27s.

6. Reconfiguration master

When the number of nodes in the cluster (Node Membership) changes, a node will be used to complete the reconfiguration. This node is responsible for sending reconfiguration messages to other nodes in the cluster, receiving feedback information from other nodes, and modifying some configuration files of the cluster (e.g. OCR, VF) to reflect the new number of nodes in the cluster.

Typically, the lowest numbered node in the cluster is selected as the primary node for reconfiguration.

7. Reboot time

This cluster parameter is used to specify the time that the Orac le cluster requires the OS to complete the restart. The default value is 3s.

8. diagwait

This parameter value is used to specify the margin time for the oprocd process. This parameter only applies to 10gR2 and 11gR1 versions of the cluster, and can only be set to 13.

If this parameter is set, the margin time of the oprocd process is calculated as follows:

margin time = diagwait (13) - reboot time (3) = 10 s。

9. Incarnation

This is an integer that grows in one direction, increasing by l for each reconfiguration of the cluster. Oracle uses this value to identify the latest state of the cluster.

Thank you for your reading. The above is the content of "What are Oracle cluster terms and parameters?" After studying this article, I believe you have a deeper understanding of Oracle cluster terms and parameters. The specific use needs to be verified by practice. Here is, Xiaobian will push more articles related to knowledge points for everyone, welcome to pay attention!

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