Network Servers

5. Back-up and Protection

Your network server may fail at some point. If it does, you need to know that you will be able to start working again within a short time.

There are many actions you can take to minimise the risk of failure or disaster, and to help you restore your system quickly and completely after any incidents.

5.1 Fit your network server with an uninterruptible power supply (UPS).

This is basically a large battery which powers the server during power cuts and eliminates power surges.

• The UPS should be compatible with your network operating system and your network management software. This is so the UPS can shut down the network in an orderly fashion.

5.2 Back up your data from the network server's main hard disk.

• Choose a convenient, high-speed back-up device, such as DAT or DLT tape drives.
• Check that the back-up device can automatically back up at least one day's worth of new data.
• Automate the procedure, using back-up software which is compatible with your server's operating system. This allows you to do back-ups at pre-set times when the system is not being heavily used.
• Use a cycle of back-up tapes to record new data every day and a full copy of the entire hard disk every week.
• Store a full copy of the system off-site.

5.3 You can protect against data corruption by using fault-tolerance methods.

• Use a RAID or mirroring system to protect you against failure of an individual hard disk drive. With mirroring, the system software keeps two copies of everything and will automatically use the mirrored copy if the first copy fails.
• Install a second network adaptor card to allow you to switch cards if there is a fault. This can also speed up the rate at which data is transferred.
• Ask if databases use transaction logging and have roll forward capabilities. This keeps track of all amendments to the main data file and enables them to be applied to the last back-up.

5.4 Use firewall hardware or software to prevent unauthorised access from the outside world, such as via the Internet.

You will need firewall protection if you have a permanent connection (for example, broadband or ADSL) to the Internet. (See Security and the Internet.)

• A firewall checks incoming and outgoing traffic before it reaches or leaves the main network server.

5.5 Use anti-virus software specially designed for servers to protect against virus attacks.

Regularly check the anti-virus software supplier's website to update the list of recognised viruses held by your system.

If this list is always up to date you will have good protection against virus attack.

• Use the software to check all files stored on your network server.