1C:Enterprise 8 server cluster represents a set of work processes that manage the interaction with a set of information bases.
In comparison to 1C:Enterprise 8 application server, a server cluster provides greater reliability, scalability and utilization of hardware resources.
The Main Features of Server Cluster
A server cluster may run on one or several PCs (working servers).
Each working server may execute one or more work processes handling client connections within the cluster.
Connection of new client PCs to a cluster’s work processes is performed based on analysis of long-term statistics for work processes load.
Interaction of cluster processes with client applications, database server or with other processes is implemented through TCP/IP protocol.
Server cluster processes can be started as application, or as OS service.
Scalability of Server Cluster
Scalability of the server cluster can be implemented in several ways:
By increasing the number of work processes running at a particular server.
By increasing the number of working servers forming a cluster.
Having several work processes allows reducing the load compared with a single work process, on the one hand. On the other hand, this way it utilizes a working server’s hardware resources more effectively.
Also, running several work processes improves the server’s reliability, due to isolation of groups of clients working with different information bases.
There is a server cluster administration utility implemented as a snap-in for Microsoft Management Console (MMC). The utility can be used for the following actions:
Server cluster administration.
Streaming analysis of DBMS deadlocks.
Control for blocking user connections to information base.
Fault Tolerance of Server Cluster
The fault tolerance feature is provided in three ways:
Cluster redundancy. Several clusters can be grouped, where one cluster is a master in the group, and others are slaves. Slave clusters only read working information from the master (serving clients) and check if there is a master cluster working. If there is no master cluster, then one of slave cluster declares itself master and starts serving client requests.
Working process redundancy. There are three usage options for any working process: ’Use’, ’Use as Reserved’ and ’Do not Use’. If some working process is terminated abnormally, a cluster stars one of inactive processes and distributes the workload to that process.
Cluster has a client connection log and creates a connection session for every client. In case of physical connection failure, a cluster waits for the connection with the user to restore. In most of cases, after connection restoration the user can continue working from the point where it had stopped.
Building a Server Cluster with Various Operating Systems
Server cluster running various operating systems
All server cluster processes can work under the control of Windows® or Linux® operating systems. By using TCP/IP, a server cluster may work with servers with different operating systems.
However, there are some limitations for working servers running in Linux® OS:
Such working servers cannot interact with MS SQL Server.
Operation with COM-objects is not supported.
Kerberos protocol is used for server authentication.
Operation with Internet-connection is not available.
