I am clustering data using k-medoid. I used Davies–Bouldin index for $2$ to $n-1$ clusters. Here $n = 100$ (using smaller test case). I find minimal value of the index for 98 clusters. But the overall accuracy rate for 98 cluster is very small (smaller than 1). Here accuracy rate is how accurately test data is matched to training data. What should I do in that situation. If dataset is larger then finding Davies–Bouldin value from $2$ to $n-1$ is large task. What should I do for larger dataset?
Here is my plot of Davies–Bouldin index value for cluster solutions [X axis "index" is actually the number of clusters in a solution].