Let’s watch the controller getting through the Web Server pattern with caching enabled:

This pattern has no write requests, so the RAID5 arrays are very fast. Mirror arrays are also doing very well. However, the requests queue being 256, the RAID10 is behind the four-disk RAID10 (we saw something like that in the Database pattern), while the RAID1 has a mysterious slump in the graph at requests queue = 64. The graphs of the RAID0 arrays haven’t changed their shapes since the File Server pattern.

These are the ratings of the arrays, which we calculated by the same formula as in the File Server pattern:

There are no writes to be performed, so RAID1, RAID10 and RAID5 arrays all show very high speeds. Each of them outperformed the RAID0 of the same number of drives, while the RAID10 is the best of all here.

Let’s compare four-disk arrays with different caching types.

There is nothing to optimize as there are absolutely no write requests! Thus, the status of the cache of the controller and the drives has no effect on the array performance.