Performance in Intel IOMeter FileServer and WebServer Patterns
Let’s watch the controller handling the test that imitates the workload on the disk subsystem of a typical file or web server.
The File Server pattern comes first:
The same table, but in the graphical representation:
There are only 20% of write requests here, so all the arrays show high results. RAID0 arrays have good speed scalability depending on the number of drives in them. The four-disk RAID5 array is nearly as fast as the three-disk RAID0 array. The performance of the RAID10 approaches that of the four-disk RAID0 and this means that the algorithm of optimized reading from the mirror works well here. The speed of RAID1 is a little lower than of the single drive, as it doesn’t use the optimized reading algorithm.
Let’s compare the performance of the arrays using a rating system. We calculate the performance rating for each array by averaging the controller speed under each type of workload:
The four-disk RAID0 is on top, closely followed by RAID10. The three- and four-disk RAID5s are slightly slower than two- and three-disk RAID0s, respectively. The small writes share didn’t help much to the RAID1: it even fell behind the single drive.
Let’s see what we have after the lazy write algorithms have been disabled:
As you see, 20% writes is enough for the arrays to suffer a performance loss from disabling lazy writing to the drives.
That’s how it tells on the array performance:
So the performance hit amounts to 11-17%.