作業系統叢集如何運作
HCL Domino ®所使用的群集方法稱為應用程式群集。
Domino ®是一個應用程序,它監視叢集並根據您設定的參數確定何時進行故障轉移和工作負載平衡。另一種形式的叢集是作業系統叢集。
在這種形式的叢集中,作業系統監視叢集並確定何時應進行故障轉移。當發生故障轉移時,故障轉移到的伺服器(稱為節點)將接管故障節點的資源、存取故障節點正在存取的儲存空間,並執行故障節點正在執行的應用程式。
執行作業系統叢集有兩種基本方法:主動對被動和主動對主動。在主動對被動叢集中,被動節點並不執行本身的應用程式,而是待命,若有主動節點失敗時加以接管。在主動對主動叢集中,節點全部執行其本身的應用程式,但叢集中的其他節點如果失敗,也可以負責接管。此外,還可將作業系統叢集架構成為,只有硬體故障時才移轉,或是硬體故障或軟體失敗時都會移轉。
由於Domino ®使用應用程式集群,因此本節不提供有關作業系統集群使用的各種方法和配置的詳細資訊。但是,因為您可以將Domino®與多個作業系統叢集一起運行,包括高可用性叢集多處理 ( HACMP ™ ) 和Microsoft ™ Cluster Server (MSCS)。Server
Operating system clusters provide failover that is transparent to users. Because the receiving node takes over the resources of the failed node, the user sees the same server name and same network address as on the original server. Unlike many operating system clusters, Domino® clustering does intelligent failover. When a server fails, Domino® checks its cluster cache to find the server that is most available in the cluster. Domino® also lets you actively control workload balancing, which operating clusters may not offer. In addition, Domino® clustering lets you set up clusters of servers that run different operating systems, while operating system clusters require that all nodes run the same operating system.
To run Domino® in an active-active cluster, you must use Domino® partitioned servers on the nodes. Doing so lets each node take over the tasks of the other node while also maintaining its own tasks.
若要使用主動對主動架構,您必須確定萬一移轉發生時,每個節點都能處理另一節點的工作量。
Benefits of using OS clusters with Domino® clusters
- Most Domino® agents do not fail over, so when a server fails over in a Domino® cluster, agents that were running do not continue running on the new server. If these agents are configured to run on a specific server, they will not be able to run on another server after Domino® failover occurs. In an operating system cluster, however, the same server name is used after failover occurs. Therefore, the agents can run on this server. In an operating system cluster, agents that were running on a schedule when failover occurred will restart the next time they are scheduled to run.
- If you have applications that use hard-coded server names, the applications will not work if they fail over to a different Domino® server. These applications will run after failing over in an operating system cluster, however, because the server name is still the same.
- If a user is editing a document when the server fails, the user can't save the document in a Domino® cluster. The user has to paste the document into a replica on the new server. In an operating system cluster, however, users can save documents that they were editing when the server failed.
- The Administration Process does not fail over in Domino®. Therefore, it is useful to set up operating system clusters for your administration servers.