When planning your backup strategy you need to consider the path that data takes to your backup servers and from there to your tape drives or disks. Whichever is the slowest point in the chain will determine just how fast your backups can run.

Below are some metrics that give rough throughputs for networks, backup devices etc to help you plan your backup and know in advance just what sort of throughput you are likely to get. All you then need to do is multiply the slowest link in your chain by the number of hours of your backup window and then you know just how much data you will be able to backup – remember that bonding cards together or adding backup devices to a tape library will increase your data throughput (simply multiply the figures below).

Network Transfer Rates

SCSI Transfer Rates

Fibre Channel Transfer Rates

Tape Drives

So, don’t buy a DLTS4 drive to run over a 1GB link, you may as well save some money and buy a less capable drive as your link will slow you down. And do consider streaming multiple backups to the same backup device or using multiple older backup devices to take account of faster links.