In addition to the necessary technical resources, the personnel cost of backing data up is also often underestimated. We have already discussed (1) how the backup of data has to be continuously adapted to the ever-changing IT landscape; and (2) that it is necessary to continuously monitor whether the backup of data is actually performed according to plan. Both together quite simply take time, with the time cost for these activities often being underestimated.
As is the case for any activity, human errors cannot be avoided in backup, particularly if time is always short due to staff shortages. However, in the field of data protection these human errors always represent a potential data loss. The costs of data loss can be enormous: for example, Marc Farley (Building Storage Networks, 2000) cites a figure of US$ 1000 per employee as the cost for lost e-mail databases. Therefore, the personnel requirement for the backup of data should be evaluated at least once a year. As part of this process, personnel costs must always be compared to the cost of lost data.
The restoration of data sometimes fails due to the fact that data has not been fully backed up, tapes have accidentally been overwritten with current data or tapes that were already worn and too old have been used for backups. The media manager can prevent most of these problems.
However, this is ineffective if the backup software is not correctly configured. One of the three authors can well remember a situation more than ten years ago in which he was not able to restore the data after a planned repartitioning of a disk drive. The script for the backup of the data contained a single typing error. This error resulted in an empty partition being backed up instead of the partition containing the data.
The restoration of data should be practiced regularly so that errors in the backup are detected before an emergency occurs, in order to practice the performance of such tasks and in order to measure the time taken. The time taken to restore data is an important cost variable: for example, a multi-hour failure of a central application such as SAP R/3 can involve significant costs.
Therefore, staff should be trained in the following scenarios, for example:
- restoring an important server including all applications and data to equivalent hardware
- restoring an important server including all applications and data to new hardware;
- restoring a subdirectory into a different area of the file system;
- restoring an important file system or an important database;
- restoring several computers using the tapes from the off-site store;
- restoring old archives.
Data protection is a difficult and resource-intensive business. Network backup systems allow the backup of data to be largely automated even in heterogeneous environments. This automation takes the pressure off the system administrator and helps to prevent errors such as the accidental overwriting of tapes. The use of network backup systems is indispensable in large environments. However, it is also worthwhile in smaller environments. Nevertheless, the personnel cost of backup must not be underestimated.
This chapter started out by describing the general conditions for backup: strong growth in the quantity of data to be backed up, continuous adaptation of backup to ever-changing IT systems and the reduction of the backup window due to globalization. The transition to network backup was made by the description of the backup, archiving and hierarchical storage management (HSM). We then discussed the server components necessary for the implementation of these services (job scheduler, error handler, media manager and metadata database) plus the backup client. At the centre was the incremental-forever strategy and the storage hierarchy within the backup server. Network backup was also considered from the point of view of performance: we first showed how network backup systems can contribute to using the existing infrastructure more efficiently. CPU load, the clogging of the internal buses and the inefficiency of the TCP/IP/Ethernet medium were highlighted as performance bottlenecks. Then, proposed solutions for increasing performance that are possible within a server-centric IT architecture were discussed, including their limitations. This was followed by proposed solutions to overcome the performance bottlenecks in a storage-centric IT architecture. Finally, the backup of large file systems and databases was described and organizational questions regarding network backup were outlined.
This chapter ends our consideration of the use of storage networks. In the remaining three chapters we concern ourselves with management of storage networks, removable media management, and the SNIA Shared Storage Model.
Use the following table of contents to navigate to chapter excerpts or click here to view Network Backup in its entirety.
|ABOUT THE BOOK:|
|Storage networks will become a basic technology like databases or local area networks. According to market research, 70% of external storage devices will be connected via storage networks in 2003. The authors have hands-on experience of network storage hardware and software, they teach customers about concrete network storage products, they understand the concepts behind storage networks, and show customers how storage networks address their business needs. This book explains how to use storage networks to fix malfunctioning business processes, covering the technologies as well as applications -- a hot topic that will become increasingly important in the coming years.Purchase the book from Wiley Publishing|
|ABOUT THE AUTHOR:|
|Authors Ulf Troppens and Rainer Erkens are both employed at IBM TotalStorage Interoperability Center in Mainz, Germany a testing, development and demonstration laboratory for storage products and storage networks. Both authors work at the interface between technology and customers. Wolfgang Müller is currently working as a software architect in the Storage Software Development Department at IBM in Mainz, Germany, where the focus is on software development projects supporting open standards such as SMI-S/CIM/WBEM and IEEE 1244.|