Regardless of whether you leverage fibre channel- or SCSI-based RAID arrays, you must closely monitor the data path between the RAID arrays and your server. Each disk can provide a certain amount of throughput. As you group more and more arrays on a particular channel, you need to ensure that the data path between your arrays and your server doesn't become saturated. To avoid saturation, select the RAID array technology that meets your needs. Fibre channel can run at speeds up to 100Mbps, and the latest SCSI standard can support speeds up to 80Mbps. Follow the data path from the disk to your NT system. You can take this precaution to ensure that you haven't configured too many RAID arrays and avoid overwhelming the data channel, the disk array controller in the RAID array, the RAID adapter in the NT system, or even the PCI bus that the RAID adapter attaches to.
NT doesn't provide any one counter in Performance Monitor to accomplish this task, but you can review Performance Monitor's LogicalDisk object's Disk Bytes/sec counter for each array connected on a specific channel, add these values together, and ensure that they aren't exceeding 70 percent of the theoretical throughput your data path can support. If the total does exceed this threshold, consider adding a second data (SCSI or fibre channel) connection to your RAID array configuration. The converse of this concept is helpful also. If you have plenty of bandwidth available from your current data channel, you can use this data channel even further by adding more RAID arrays.