A B C D E F
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Centralised Backup Backup systems can soon proliferate on a network, with each sever requiring its own local backup device. A centralised backup system pools a network’s backup resources, and a result, can greatly simplify schools network administration, for example, by making it easier to automate the backup process. Centralised backup can also save you time, money and resources - for example, requiring fewer tape drives.
Individual Backup Network Centralised Backup
Tape Autoloader or library
Network Servers with integrated tape drives
Not easy to manage or monitor
Difficult to expand as the amount of data on your network grows
Many tapes required as each server will require its own backup set
Manual intervention needed to change tapes
Network Server with no local backup
Centrally managed with simple monitoring Faster to backup and restore Fewer tapes required as each tape is fully utilised Easy to manage and monitor
Centralised Storage System in which storage is consolidated, rather than using multiple local storage devices on a network. Centralised storage can offer your school many benefits including, lower costs, greater efficiency, scalability and simpler network management, for example, in maintenance and backup. It’s also possible to allocate storage space to individual servers intelligently. Various centralised storage solutions are available, one of the most efficient and flexible being a Storage Area Network (SAN).
CHAP (Challenge Handshake Protocol) Authentication system mainly used by Point-to-Point Peer (PPP) servers, which is more secure than a password-based system. CHAP uses a three-way handshake system which involves a server sending the peer a challenge message at random intervals. The peer responds with a hashed value, which is checked and authenticated by the server. If authentication fails, the connection is terminated. CHAP is supported by the iSCSI protocol.
Citrix US company which offers various optimised thin client solutions.
A SPOTLIGHT ON… Snapshotting and Replication
Snapshotting creates a point-in-time copy of data or the state of a system, allowing you to restore data from a specific point-in-time. Snapshotting, makes it easy to replicate data between disk arrays, for example, and it can reduce both the RTO (Recovery Time Objective) and RPO (Recovery Point Objective). This makes snapshotting a very useful disaster recovery tool.
However, in order for snapshotting to be fully effective, it’s vital that your data is in the correct state during the snapshot operation. For example, if a database is running whilst a snapshot is being created, some of its files will be in an open or unstable state. As a result, there is a high risk that the data could become corrupted - a condition known as crash consistent. The effect is similar to what happens if you were to pull the plug on a server before closing down all files and applications. At best, it will take longer to recover the data, but at worse, the data may be lost or unreadable when attempts are made to restore it.
For this reason, it’s vital that any files or applications are closed before a snapshot is taken. One way of protecting data during snapshotting is to initiate a process called quiescing. This puts the data in a temporary inactive or inhibited state, and has two benefits. First, the data is stabilised or application consistent. This makes it possible for you to recover the data in its original state if required. The second benefit is that applications can be reactivated much faster than if they had been closed down completely.
Snapshotting can be a very useful process, but you should always ensure that your data is one hundred per cent secure before carrying out the procedure. Note that configuration of snapshotting and replication is complex and costly to implement. In an educational environment, these factors can outweigh the benefits, and so careful consideration should be given to its implementation.
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