title: Frequent random access of large arrays
body: <p>I have to implement 4 Hash Tables. The size of hash tables are going to be very large ~ 1 GB Each. The hash values will be the address of accessing the data. Now, since the hash values will be randomly distributed, I have to insert and read data from the hash tables randomly. What is the best way to implement such a design? I cant use the arrays in RAM since it will cause overflow. Will I be benefited by using the mmap? Or any other design scheme.</p>
  
  <p>Any help is highly appreciated. </p>