Sequential read/write speed

The first battery of tests is about sequential read/write speed, a discipline where platter-based disks traditionally show quite good results.

Let's start with read speed: 

RAID10 Sequential read speed

It seems that different layouts bring very different results! At low queue/thread count, the “far” layout is the winner, showing RAID0-like performance. However, ramp up threads and you see another picture, with the “offset” layout clearly on top. The default “near” setup seems in bad light here.


Now, write speed: 

RAID10 Sequential write speed

The curves are more similar now, but somewhat reversed: we see the “far” layout quite behind in single thread mode, but at “offset” level with high thread count. The “near” layout has a flatter curve, being superior in 1-thread scenario but inferior with over 4 threads.

Mixed (50% read – 50% write) results: 

RAID10 Sequential mixed (read/write) speed

All layouts perform similarly here.

Summarizing, the only significant differences are in sequential read test, were “offset” and “far” are clearly superior to “near” layout. However, sequential speed rarely are so important in the server world, as many workloads issue random I/O operations.