The measurements below show - on the basis of an overload on one channel - the improvements in throughput when further channels are attached. The load is configured in such a manner that one free alias device is always available for each task in order to make optimal use of the channels.
Channels | PAV | Vol. | Tasks | Read | Write | Random25 | |||
IO/s | Mbyte/s | IO/s | Mbyte/s | IO/s | Mbyte/s | ||||
1 | Yes, 3 | 6 | 12 | 27,100 | 584 | 26,200 | 603 | 26,700 | 766 |
6 | 24 | 28,000 | 585 | 28,000 | 606 | 27,600 | 767 | ||
2 | 6 | 24 | 53,300 | 1,175 | 51,300 | 1,222 | 52,200 | 1,519 | |
2*2 | 12 | 24 | 79,900 | 1,956 | 68,400 | 1,852 | 76,100 | 2,247 | |
Basically FC connections scale very well, which means that with n channels almost an n-fold throughput can be achieved. This can be understood clearly on the basis of the throughput increase when switching from one to two channels.
When this figure is doubled again to four channels, however, the throughputs and IO rates measured are so high that the performance of the SU700’s IO system is exhausted. The four channels (which after all correspond to 32 of the 1-Gbit channels of the preceding generation) can no longer be fully utilized here.
However, this does not mean that four channels must always be regarded as sufficient. Further explanations and recommendations on this subject can be found in section "FC connection".