LAN backup tip: Learn how to perform LAN-based backups without placing a burden on your network and reduce the impact of poor network performance on your backups.
There are several factors that can impact LAN-based backup
- Where the source data being backed up is located
- How the server is attached or is accessing the source data for backup
- How the data is moved to a target backup destination
- The type and amount of data to be backed up
Various techniques and technologies can be used in different combinations to optimize backup performance. Examples include data compression, compaction, and file and data differencing (also known as deduplication) which reduce the amount of data to be moved, as well as the amount of data actually sent over a network. Another variation is to compress and compact the data as efficiently as possible -- similar to zipping a file to speed up data transmission. Yet another option is to maintain a local disk cache where changed data can be temporarily stored as a form of disk-to-disk backup until a later time when network bandwidth is available.
LAN backup information The difference between LAN-free and serverless backup
The path from disk to tape in a LAN-free backup
Other techniques involve scheduling backup data transmission to run at times when networks are not as busy, along with bandwidth throttling. Before upgrading your network, investigate where the bottlenecks are occurring along with how resources are being used. You may be able to do some network or backup tuning, such as using larger transfer packets, jumbo frames and various TCP window sizes.
Data protection management (DPM) tools, from vendors including Aptare, Bocada and WysDM, provide insight into how backups are performing from a historical and real-time perspective. Some DPM tools provide additional analysis and event correlation for rapid problem determination and resolution as well as planning for backup tuning. Network-centric tools including analyzers, sniffers and diagnostic devices are available from vendors including Anue, Network Instruments and others.
Backup of network attached storage (NAS) filers can be accomplished using the network data management protocol (NDMP) to efficiently move data over a network from source to backup target devices. NDMP can also be used to manage movement of data from backup sources to direct attached backup devices using SAS, SATA, SCSI or Fibre Channel to off load LAN networks.You can learn more about NDMP along with NDMP compliant technologies at www.ndmp.org.
For long distance networks and remote backup, bandwidth acceleration and optimization technologies such as write acceleration along with wide area data services (WADS) (also known as wide area file services), can be a benefit. These and other technologies are available from a number of vendors including Brocade, Cisco, McData, Netex, Packeteer, Riverbed and Signiant among others.
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Greg Schulz is founder and senior analyst with the IT infrastructure analyst and consulting firm StorageIO. Greg is also the author and illustrator of "Resilient Storage Networks" (Elsevier) and has contributed material to "Storage" magazine and other TechTarget venues.
This was first published in September 2006