Next goes the web-server-emulating pattern:

The shape of the graphs of the RAID0 arrays hasn’t changed much as compared with the File Server pattern, but the speed of the arrays has become lower. The RAID5 arrays have become much faster since the Web Server pattern has no write requests and is the most optimal operating mode for such arrays. This is also why the mirroring RAID1 and RAID10 arrays that alternate read requests between the disks of the mirroring couple are faster than the 2- and 4-disk RAID0 arrays.

We calculated the performance ratings of the arrays like in the File Server pattern, i.e. by averaging their speeds under different loads:

The RAID10 and RAID5 caught at the opportunity to work without any write requests and the RAID5 arrays are not only one step higher in the results table but have also nearly reached the performance of the RAID0 arrays built out of the same number of disks. The RAID10 has the highest performance, while the RAID1 is far ahead of the 2-disk RAID0.

Here are the results of the controller in WriteThrough mode:

These graphs show that lazy writing has no effect on the performance of the arrays in this mode, i.e. when there are no write requests at all.

We’d also want to single out the brilliant performance of the RAID10 array which is faster than the RAID0 at all loads!

Lazy writing should not affect the speed of an array in this writes-free pattern and this is exactly what we see in the diagram.