The underlying hardware components determine the maximum throughput of network backup systems. The software components determine how efficiently the available hardware is actually used. At various points of this chapter we have already discussed how network backup systems can help to better utilize the existing infrastructure:
- Performance increase by the archiving of data: deleting data that has already been archived from hard disks can accelerate the daily backup because there is less data to back up. For the same reason, file systems can be restored more quickly.
- Performance increase by hierarchical storage management (HSM): by moving file contents to the HSM server, file systems can be restored more quickly. The directory entries of files that have been moved can be restored comparatively quickly; the majority of the data, namely the file contents, do not need to be fetched back from the HSM server.
- Performance increase by the incremental-forever strategy: after the first backup, only the data that has changed since the last backup is backed up. On the backup server the metadata database is used to calculate the latest state of the data from the first backup and all subsequent incremental backups, so that no further full backups are necessary. The backup window can thus be significantly reduced.
- Performance increase by reducing tape mounts: the media manager can ensure that data that belongs together is only distributed amongst a few tapes. The number of time-consuming tape changes for the restoring of data can thus be reduced.
- Performance increase by streaming: the efficient writing of tapes requires that the data is transferred quickly enough to the tape drive. If this is not guaranteed the backup server can first temporarily store the data on a hard drive and then send the data to the tape drive in one go.
- Performance increase by backup on volume level or on block level: as standard, file systems are backed up on file level. Large file systems with several hundreds of thousands of files can sometimes be backed up more quickly if they are backed up at volume level. Laptops can be backed up more quickly if only the blocks that have changed are transmitted over the modem to the backup server.
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.|