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1. Product Overview
2. Product Components
3. Benefits of Using Two Network
Cards
Product Overview
ClusterReplica
is a cluster software that features data replication and server availability solutions. It includes functionalities of data replication, registry replication
and failover.
MS SQL server failover and database file replication highlights
ClusterReplica.
ClusterReplica
binds two Microsoft Windows systems together to function as one server, so that
there will be at least one system running normally to server the network
clients’ requests.
Of
the two systems clustered together, one is taking the ACTIVE role to be the
Primary station, and the other taking the STANDBY role to be the Secondary
station. During standard condition, both systems are running normally, the
Primary station will service the network clients directly and replicate all
newly changed data to the Secondary station to keep it current with all data.
This
continuous data replication works on open and locked files including the
database files. The process ensures all changed data updated at all time. No
data will be lost due to system failure or the service down, and server service
should be available 24/7.
Current
version of ClusterReplica is the Small Business Edition. It operates on the
clustered systems of two Windows 2000, 2003 or XP systems. Minimum requirements
are:
- RAM:
128MB and above
- Hard
disk: 8GB or larger
- Two
nodes cluster
system running Windows 2000/2003/XP systems with most
current updates
- Ethernet
connection of a HUB or SWITCH
- The
two nodes must be in the same subnet
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Product Components
File
Replication - ClusterReplica
is specially designed for database applications. It is capable to perform
real-time, open-file replication on database files, and automatic failover/failback
operation. When File Replication involves an application which runs its own
service, both File Replication Setup and Application Failover Setup must be
correctly configured to ensure
proper failover.
Registry File Replication -
The Registry
Replication functionality meets the needs of some server systems that require
certain dynamically changed key definitions in the registry matched on the
Secondary server for a successful failover.
Share
Folder for File Replication - If you have drives or
folders shared out for network usage (through Windows "map network
drive"), you will need to setup this configuration to ensure the drives or
folders to be properly shared out on the Secondary server when the Failover
occurs.
Failover/Failback
Solutions
-
ClusterReplica provide
two levels of Failover: Service level and System level Failovers.
Though both will result the automatic role switch of the Secondary to become the
Primary station, the two types of Failover are not handling the situation in the
same way.
Failback in ClusterReplica functions a little different from standard
concept. With its unique design of Failover, ClusterReplica switches the
roles of ACTIVE and STANDBY stations when Failover takes
place. Because of this special design, Failback is not mandatory.
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Benefit of Using Two Network Cards
For
a cluster server, there are internal communication between the clustered systems
as well as external communications between the server and clients. The internal
communications involve file replication, system and application configurations,
and all server environment specifics. These are the things you want to keep from
outsiders.
By
installing two network cards on each of the clustered systems, the internal and
external communications are separated. One set of IPs can then be devoted
strictly to the internal communications of the clustered systems without the
interference of the public network traffic.
This
example sets the 195 network for internal communication, the 123 network for
external communication.
As shown, the public network traffic will go to the ACTIVE server through the IP
address of 123.123.123.10 without interference with the cluster server's
internal activities which is utilizing the 195 network.
The
effect on this setting of two network cards is remarkable. From security
standpoint, the separation of the internal and external traffic on the cluster
server totally eliminates the possibility of public interference of the
servers’ internal activities. For this reason, data encryption for file
replication process between the clustered systems will be unnecessary.
With
the same footing, the improvement of performance is also notable. First, with
two subnets, network traffic is reduced. Secondly, each set of IP addresses
devoted to specific tasks, efficiency increased. And lastly, because no
encryption is applied, efficiency improvement can be significant.
You
need only one pair of IPs to install ClusterReplica. This pair of IPs will be
responsible for the internal communication of the clustered systems. So, when
running systems with two network cards, make sure you don’t mix up the
internal and external pairs of IPs.
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