Business continuity plan for networks
A business continuity plan is a document that defines the major threats that a company will face, including any disasters, and sets up the policies and procedures that will have to follow, to ensure the business resumes with the minimum of delay. This plan is developed after a very careful assessment and analysis of the risks and the impact of each of the types of disasters and events that could happen. Parts of a business continuity plan include:
Disaster recovery plan
This plan defines the recovery procedures after a disaster strikes.
Business recovery plan
The Business recovery plan describes the procedures to resume the normal everyday business functions at an alternate site after the disaster.
Business resumption plan
This type of plan describes the procedures to resume functions of the critical systems in order to go back to business as normal. Information such as contact lists is vital.
Contingency plan should describe the procedures to resume business as normal after a disaster strikes or also when an unforeseen event happens during the recovery process already taking place.
A Utilities plan is essential for network services which should include electricity, Uninterruptible Power Supplies (UPS), and power generators. UPS systems are useful when there is no power, but they will only last for a small amount of time. If the power outage lasts for longer periods, then you might have to look at a power generator to supply essential electricity to the network.
High availability and fault tolerance.
The High availability is the maximum up time along with the efficiency of the systems and the network. This can be achieved if there are good arrangements to maintain network services in case of a system failure. Network load balancing is a method used to share the load of requests for particular services, including web servers or a DNS server. Server clustering is another method to ensure very high availability. You can implement a Redundant Array of Inexpensive Disks (RAID), which are also known as fault-tolerant disks. Servers that are equipped with RAID systems allow hot swapping of hard disks so that the server does not have to be taken offline when a failed disk needs to be replaced.
There are a number of types of fault-tolerant RAID systems including:
RAID 1 (Disk Mirroring)
This type of RAID system uses exactly two hard disks, preferably they are the same size and make. The data is then written to one of the disks and is copied to the second disk. In this type of setup, the disk utilization is only 50 percent.
RAID 5 (Disk Striping with Parity)
This type of RAID system uses 3 to 32 disks, again preferably of the same size and make. Then the data is evenly written to all the hard disks simultaneously. The failure of a single disk does not bring down the server.
RAID systems can be running as either hardware or software based. a hardware-based raid system is more expensive but much more efficient than a software alternative.