Tuning RAID controllers is not as difficult as some vendors would have you believe; there's no need for professional services to get the job done.
Many of the parameters reside around the cache and cache usage, along with the obvious tunable parameters for the RAID LUNs. This article isn't about tuning specific RAID controllers; for that, you will need to spend some time reading the documentation, but hopefully by reading this you will be able to consider the parameters in context with the I/O of the whole system. Each vendor has its own nomenclature for variable names and what they mean. As there is no standard set of definitions, I have chosen my own, which you should be able to apply to a specific vendor. The areas that need to be considered are: LUN creation and RAID level, and cache tuning and configuration.
Figuring out what RAID levels to use has been pretty well covered (see RAID Storage Levels Explained), so we'll stick to the subject of RAID tunables here. If you configure RAID to optimize your system, whether that be a RAID controller card on your PC or a high-end mission-critical enterprise RAID array, you should have a good understanding of what to consider after reading this article.
We'll start by considering what type of RAID controller you have. Today they can be broken down into three categories:
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