XLink ClusterReplica SQL 3.0 For Windows 2000/2003/XP

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XLink ClusterReplica SQL 3.0

For Windows 2000/2003/XP

White Paper

XLink Technology, Inc 1546 Centre Pointe Drive Milpitas, CA 95035, USA

For the latest Product Information and free demo program, please see www.xlink2.com

Abstract

The fast advancement of internet communication and business processing

models have pushed business owners to take serious concern on network server availability and data protections.

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Today’s Challenges on Data Protection and Availability

for Small Businesses

The high-speed network interactions in all types of business dealings brought with it the challenges on data availability and management to small business owners. Major characteristics of this growing business model include:

• Exploding data increases difficulty in data management

The paperless office has become the norm of today’s business style. Data exchange over high-speed internet, database file processing and internal documentation updates are the major sources in this data exploding trend. This dramatic increase in amount of data amplifies difficulties in data

management and data processing.

• Business globalization requires non-stop server service

The advancement in internet services made the globalization possible for small businesses. Customer satisfaction demands 24x7 flawless server services and accurate, fast data processing. Real-time data replication and automatic cluster failover are the keys for this customer satisfaction which in turn ensures the success in this global market competition. • Files and data must not be lost in any circumstances

Files of personal information and business documentations are important business assets that need protection from being damaged or lost by natural disasters and human errors. Ability to save all new data at the time it is created is crucial to prevent data loss.

• Cost-effective

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Solution: Server Clustering

The most effective solution to satisfy all conditions brought up in above section is server clustering. Server clustering binds two or more computer systems together to server a common purpose. Typically, there are data replication activities

between the clustered servers and the failover capability to ensure server available.

A Speculative Solution: server clustering software for large companies Most of today’s clustering solutions that are currently available to businesses are typically designed for large sized companies. Large companies have well defined management structures and complex products and sales distribution methods. With these characteristics, large companies’ needs for server clustering cannot be simplified.

Server clustering, by itself, involves intricate interaction between the clustered servers. Software products designed to create and manage the clustering tend to be complicated and difficult to understand. Installation and configuration of this kind of software are especially beyond the capacity of an average small business owner.

These products are usually very expensive to buy and require trained IT staff to configure and maintain. They typically meet the needs and budget of large companies, but are impractical for small businesses.

The Solution: XLink ClusterReplica for small businesses

ClusterReplica SQL 3.0 is a Microsoft Windows server cluster solution specially designed for small businesses. This edition emphasizes on Windows MS SQL database server clustering for data protection and availability. The automatic data replication configuration for MS SQL database files and automatic initial database file sync between the clustered systems set the cluster server ready to run after an easy installation of the software.

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The automatic failover capability of ClusterReplica SQL 3.0, when detects abnormal functioning of the Primary station, switches the ACTIVE role of the cluster server to the Secondary station. This auto-failover ability guarantees server 24x7 availability.

The Technology

The Snapshot structure developed in house is the core technology for Cluster-Replica SQL 3.0 software and other products in our IsaStor series of products. Specifically for ClusterReplica SQL 3.0, the point-in-time snapshots make sure modified data of different forms and tables find their way to the correct location while being replicated to the Secondary station. This assurance is important for database files because the inter-linkage of database forms and tables requires matching data at all times.

XLink’s Snapshot Technology supports not only Windows XP and 2003 systems, but also Windows 2000 systems. This capability allows small companies using the existing computer equipments, without having to spend money on upgrade, to enjoy the up-to-date technology of clustering and further realize server 24x7 availability.

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ClusterReplica SQL 3.0 Highlights

• Active/Standby configuration - The cluster server backs up data from

the ACTIVE station to the STANDBY station when both systems are "alive". When the ACTIVE station fails to function normally for any reason, failover will take place automatically. The STANDBY station will then take up the ACTIVE role to guarantee 24x7 server availability

• Active/Active configuration - In this configuration, SQL service on both

Primary and Secondary stations are on so that users can extract data from the Secondary for data analysis and report purposes. Data replication is in real time as it is in the Active/Standby mode.

• A built-in backup utility tool is included - This tool assist users to

backup data on the cluster server to a remote (or local) location for data protection. Typically backup runs on the Secondary station so that the process will not interfere with network traffic serviced on the Primary station.

• Automatic MS SQL database file replication configuration – This turnkey feature brings convenience to those who have the need for cluster servers, but don't know enough to configure the MS SQL server

themselves and are holding back on spending money on professional IT help.

• Real time, open file data replication – The special design of MS SQL database data replication is based on its file creation requirements. When a database file is created, many forms and tables are involved. So, if one file in the database is modified, all related forms and tables must be

updated. This design guarantees successful database data replication and restore.

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ClusterReplica SQL 3.0 Benefits

• Guaranteed Server Availability

1. DNS Redirection for Cross-Network Failover – When the two systems to be clustered are in two different network segment, the common configuration of local host table or IP address for

clustering failover may not work because neither the cluster name nor the cluster IP can be used for public connection in a different network segment. In this situation, DNS setup is employed to overcome the difficulty.

2. System and Service level Failover – Failover will take place when one of the services fails to function normally. In this situation, both clustered systems will be running. However, their roles of ACTIVE and STANDBY will be switched automatically. In case when the Primary station fails, the Secondary Station will become the Primary station and work in STAND ALONE mode.

So, no matter it is the entire Primary system failed, or only one of the services on the Primary system failed, the automatic failover will take place to ensure non-stop of your server service.

• Real-Time Data Protection - ClusterReplica SQL 3.0 is specially designed for database applications. It is capable to perform real-time, open-file replication on database files. This capability protects your data from system failure and gets your clustered system data ready for failover. • Application Compatible – Besides the service level failover capability,

ClusterReplica SQL 3.0 is also capable of replicate Windows registry files. This functionality satisfies the needs for those applications which

dynamically update their registry files during operation. With the

applications’ registry files current at all times, the success of failover is guaranteed.

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How Does ClusterReplica SQL 3.0 Work: Two Examples

The most upfront decision on configuring ClusterReplica SQL 3.0 depends on how your network is set and the purpose of using the software.

Case 1: Determine the Failover Configuration

The three concepts that involve Failover in ClusterReplica SQL 3.0 are: 1. Cluster Name - the name which network clients use to connect to the

Primary station

2. Cluster IP - the IP address which network clients use to connect to the Primary station

3. DNS setup

The two types of network configuration established on above concepts that concern cluster Failover using ClusterReplca SQL 3.0. are:

1. The clustered systems are in same network segment 2. The clustered systems are in different network segment 3.

The most important condition being that the clustered systems must not be the domain controller or the DNS server.

The Failover setup considerations are summed up in following:

When both Primary and Secondary stations are in the same network segment

In this system environment, three situations can be considered: Local host table or IP address is used - the Cluster IP must be set

MS Netbios is used to resolve network address - the Cluster Name must be set

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When the Primary and Secondary stations are in different network subnet

In this system envrionment, only DNS configuration can be used for Failover setup. Enable Cluster Name or Cluster IP may result failure of cluster

Failover.

Case 2: Determine the Usage

While most people using ClusterReplica SQL 3.0 for server availability purpose, some may need it only for real-time database file backup.

The Replication-Only mode

ClusterReplica SQL 3.0 makes it easy for backup only usage. With successful installation, the software is set, by default, in replication-only mode. If default MS SQL database configuration is set on the SQL server, ClusterReplica SQL 3.0 will even do the auto file replication configuration for you. No further configuration is required for ClusterReplica SQL 3.0 to backup the database files in real-time.

The Failover/Failback mode

To activate the Failover/Faiback mode, you must configure Failover Setup of ClusterReplica SQL 3.0. For configuration details, please check out the online user’s manual for ClusterReplica SQL 3.0.

Summary

The ClusterReplica SQL 3.0 is designed for Windows 2000/XP/2003 systems. With clearly defined marketing target of small businesses, XLink places quality, low cost and easy to use as the top objectives for product design. The

XLink ClusterReplica SQL 3.0 For Windows 2000/2003/XP