Introduction to EzOpenBackup Plus by gregoria


									XLink ClusterReplica SQL 3.1
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


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.

This white paper discusses the issues and solutions in data protection and
recovery that concerns small size businesses of all types. It also introduces
XLink Technology’s ClusterReplica SQL 3.1 product.

Introduction to XLink ClusterReplica MSSQL Edition

   Today’s Challenges on Data Protection and Availability ...................................1
               for Small Businesses...........................................................................1
   Solution: Server Clustering................................................................................2
   The Technology ................................................................................................3
   ClusterReplica SQL 3.1 Highlights ....................................................................4
   ClusterReplica SQL 3.1 Benefits .......................................................................5
   How Does ClusterReplica SQL 3.1 Work: Two Examples.................................6

Introduction to XLink ClusterReplica MSSQL Edition
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
         Typically to small business owners, it is essentially important for any
         product to be cost effective. A good product must be easy to use and
         reliable. Low initial cost plus low maintenance effort and cost would add
         great value to a product.

Introduction to XLink ClusterReplica MSSQL Edition
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

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

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 3.1 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.

ClusterReplica SQL 3.1 binds two of Microsoft Windows 2000/XP/2003 systems
together to create an ACTIVE/STANDBAY type of clustering. During normal
condition, the Primary station will service the network clients directly and
replicate, at predefined point-in-time, all newly created data or modified data to
the Secondary station. This process will keep the data on the Secondary station
current at all times so that should failover take place, all data will be available.

Introduction to XLink ClusterReplica MSSQL Edition
The automatic failover capability of ClusterReplica SQL 3.1, 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 3.1 software and other products in our IsaStor series of products.
Specifically for ClusterReplica SQL 3.1, 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

Different from Microsoft’s clustering system, XLink ClusterReplica SQL 3.1 does
not require a separate files system in the cluster setting. ClusterReplica SQL 3.1
can be installed directly on the database servers so that the cluster server can
access database files locally to increase accuracy and efficiency.

Introduction to XLink ClusterReplica MSSQL Edition
ClusterReplica SQL 3.1 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

    •    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

    •    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

Besides database files, ClusterReplica SQL 3.1 can also replicate other types of
files including dynamically generated registry files. ClusterReplica SQL 3.1 is a
powerful network server application of all purposes.

Introduction to XLink ClusterReplica MSSQL Edition
ClusterReplica SQL 3.1 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 3.1 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 3.1 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

    •    Reliable and User Friendly – ClusterReplica SQL 3.1 is a turn-key
         product that with successful installation, the database files needed for
         replication are automatically set. So, without further configuration, the
         clustered system is ready to run for data replication and failover functions.
         This software shall prove to be most reliable.

Introduction to XLink ClusterReplica MSSQL Edition
How Does ClusterReplica SQL 3.1 Work: Two Examples

The most upfront decision on configuring ClusterReplica SQL 3.1 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 3.1 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 3.1. are:
   1. The clustered systems are in same network segment
   2. The clustered systems are in different network segment
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

    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

    DNS is configured - the Cluster Name and Cluster IP can be optional.
    In the case where all three situations listed above are involved, users need to
    setup the Cluster Name, Cluster IP, and the DNS configuration in Failover

Introduction to XLink ClusterReplica MSSQL Edition
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

Case 2: Determine the Usage

While most people using ClusterReplica SQL 3.1 for server availability purpose,
some may need it only for real-time database file backup.

The Replication-Only mode

    ClusterReplica SQL 3.1 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 3.1 will even do the auto file replication configuration for you. No further
    configuration is required for ClusterReplica SQL 3.1 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 3.1. For configuration details, please check out the online
    user’s manual for ClusterReplica SQL 3.1.


The ClusterReplica SQL 3.1 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
ClusterReplica SQL 3.1 software helps small business owners achieve the goal
of 24x7 server availability effectively without the financial burden.

Introduction to XLink ClusterReplica MSSQL Edition

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