Features of MCCS

MCCS has the following features:.

Service Level Fault Detection and Automatic Failover 

MCCS not only detect on hardware, but it also offers detection on resources (such as network connection, application, platform, disk, etc) as well.
Therefore, if the managed resources are not working properly, it will be either restarted or failovered to the standby server according to the defined action policies.

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MCCS supports both local disk replication and shared disk environment. Thus, it provides enhanced flexibility to make equip any type of storage for the user.

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Support Failover Group

Failover group is including the resources that can be run on only one node at a time.

Application will be switch over to standby node at critical reource is failed in a failover group.
The resources that included group are online only available node.

For example, IP Address is not onlined on an active node and standby node at same the time.
Therefore, when IP address is get failed, it and its related resources will be fail over to the standby node. 

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Parallel group is a group of resources that are taken online on more than two nodes at the same time. Parallel group cannot failover.
The opposition of this is Failover Group. The group can be online on a node in a cluster within a failover group.
However, when configured through parallel group, specified application can be online, monitored and terminated on the multiple nodes at the same time in a cluster.
For example, user would like to run backup software on both nodes and be managed by the MCCS, backup software should be online on both nodes at the same time.
You can use parallel group instead of failover group for this.

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Group is a set of collected resources dependent on one another to manage resources (ex. Network Card, IP address, disk application etc.) such as failure monitoring, recovery, failover within MCCS. It is also a set of resource to failover.
MCCS can configure more than one group in a cluster. Thus, a configuration of Active/Passive, Active/Active is made possible. (Active/Active means different services on different server)
You can configure parallel and failover goup at the same time. Each group will be managed independently by MCCS in a multi-group environment.

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MCCS is not influenced greatly by the hardware compatibility in a cluster.
Thus, there is no need to use the exact same hardware between the nodes in a cluster.

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MCCS is a high availability that can be configured with no distance limitation between nodes.
That means standby server can be easily configured on a remote site without extra charge.

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Offers Remote Management Web Console

MCCS는 인터넷 브라우저를 통하여 로컬 서버 혹은 원격 서버에서 MCCS를 제어, 관리할 수 있습니다. 
인터넷 브라우저에서 MCCS가 구성된 서버로 연결할 수 있으며, 별도의 환경 파일을 구성할 필요가 없습니다.
(기본 접속 url은 'http://ipaddress:10080/main' 입니다)

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In a generic application environment, data needed for service is not in the system that has cluster but exists in other system.
Since data does not exist, there is no need to configure disk resource. Only application program exists in general in this environment.

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Shared disk (SCSI or SAN) is connected to both servers physically.
MCCS attaches the file system on shared disk to the only active server and lock to the standby server to prevent file system corruption.

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Each local disk exists in each server and data is replicated real-time to the disk of another node.
Least unit of disk replication is in partition unit. (Recommended unit : LUN)

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Cluster is a set of nodes exchanging state information for redundant purpose.
MCCS can configure cluster within two systems. In addition, additional Ethernet network connection which is called heartbeat is used to communicate between two systems, and TCP/IP is used to send the status information.

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Node is a physical or virtual computer system with a MCCS installed and running.
Node name does not need to exactly the same with the hostname of the system, and can be set as an alias in the Cluster. Mapping  
Mapping between alias and the hostname is decided by its heartbeat network address.
Node state is related to the engine state of MCCS. Node state information is collected from MCCS  when MCCS  is, and when MCCS is not running, node state information is collected through ICMP test. 

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Resources are hardware and software components, such as network interface cards (NICs), IP address, applications, disk and etc managed by MCCS.
MCCS can monitor the state of resources and can control which are bring service online, take offline, enable and disable those.. 
There are two categories of resources in MCCS which are ‘PERSISTENT’ and ‘ON-OFF’. Most resources such as IP address, disk, process and service are ON-OFF which MCCS bring online and offline based on management policies.
On the contrary, a PERSISTENT resource such as NIC cannot be brought online or taken offline by MCCS  and only monitored the status and operation.

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SCSI-LOCK uses SAN protocol which is called SCSI-3 PR(Persistent Reservation).
This is needed to prevent any data corruption which enable only one node can access a disk volume in environment where disk volumes are shared between nodes. 

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Resource group is a set of resources with dependency and MCCS failover the entire resources in a group. 
For example, to manage the ORACLE service by MCCS, IP address that is connected by client, network interface card, disks which database is stored, ORACLE listener and server service must be enclosed by a unit which is called as Group.
Group should be configured as IP address dependent on network interface card, ORACLE server dependent on disk where database is stored, ORACLE listener dependent on ORACLE server to provide proper service.
IP address cannot be assigned without network interface card, process related to ORACLE can be bring online after disk completed online. If there is more than a group defined on a cluster, one group will failover without affecting the other groups.
There are two types, parallel and failover group, according to the service.
Please refer to "5. Resource Group of MCCS User Guide" for more details about parallel and failover group.