In a Network backup, all data resides on each server to backup will use the network media in transferring the data to the backup drive.
Network backup urgency
How urgent is a network backup to a single autoloader backup drive in a large organization? For large scale computer networking organization, it usually comprises more than 3 servers to backup in a nightly basis i.e. file server; exchange server and database application server. Having a single backup drive in each server is not practical; moreover if each server data has huge data to backup more than the capacity of the backup drive. In a weekly and monthly full backup, you will need more than one cartridge in a single session full backup. It means that you have to insert the next cartridge to complete the backup. If each cartridge takes about 2 hours, every 2 hours you have to come to the server room and insert the next tape. What a lengthy task to do. It is therefore having a network backup into a single autoloader tape drive for all the servers would be more practical; more economical; and less work for the administrator.
Network backup requirement
Network backup typically requires client-server software architecture. The backup server resides on a centralized server and the backup clients reside on every system to be backed up. You need to pay the license of each client backup for this client-server enterprise backup software. For example Veritas backup software and HP Autoloader backup drive that can load 8 cartridges can be used to solve the network backup in large organization. Beside client license, you also need to purchase the exchange backup agent for your exchange server and if you also include the SQL data backup, you also need to purchase the SQL backup agent.
I mentioned the need of gigabit switch to use in my previous article about designing the network because we need to use the network backup with huge data to backup via network in nightly basis. Network backup via 100BaseT Ethernet will not be efficient and would take long and long time to complete the full backup for all the data servers.
In a Network backup, both the switch and the server’s NIC should have the same Gigabit speed to provide a true Gigabit speed in transferring data from the servers and the tape drive. Theoretically, the network backup speed in a Gigabit environment will be 10 times faster than the normal 100BaseT environment. But typically the transfer speed factor of the backup drive will also affect the network backup speed.
Network backup strategy
Normally there are 4 types of backup strategy you can use in the network backup
1. Normal backup
All selected files and folders are backed up. The archive attribute is cleared. A Normal backup does not use the archive attribute to determine which files to back up; all selected items are transferred to the destination media. Every backup strategy begins with a Normal backup that essentially creates a baseline, capturing all files in the backup job.
2. Incremental backups
Selected files with the archive attribute set are backed up. The archive attribute is cleared. Selected files with the archive flag are transferred to the destination media, and the flag is cleared. If you perform an incremental backup one day after a normal backup has been performed, the job will contain only the files that were created or changed during that day. Similarly, if you perform an incremental backup one day after another incremental backup, the job will contain only the files that were created or changed during that day.
3. Differential backup
Selected files with the archive attribute set are backed up. The archive attribute is not cleared. Because a differential backup uses the archive attribute, the job includes only files that have been created or changed since the last normal or incremental backup. A differential backup does not clear the archive attribute; therefore, if you perform differential backups two days in a row, the second job will include all the files in the first backup, as well as any files that were created or changed during the second day. As a result, differential backups tend to be larger and more time-consuming than incremental backups, but less so than normal backups.
4. Copy backups
All selected files and folders are backed up. Copy neither uses nor clears the archive attribute. Copy backups are not used for typical or scheduled backups. Instead, copy backups are useful to move data between systems or to create an archival copy of data at a point in time without disrupting standard backup procedures
See also:
- LAN topologies -basic knowledge
- STP protocol – spanning tree protocol
- VLAN Tutorial - tutorial about VLAN
- Computer networking hardware
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