A computer receives a write request including an offset within a virtual disk. The computer writes the data block to a remote platform and calculates a hash value of the data. If the hash value does not exist in a first table of a block cache of the computer, the computer adds a pair to the first table: hash value/block cache data offset. Next, the computer adds a pair in a second table of the block cache: virtual disk offset of the data/hash value. A read request uses these tables to find the data in the cache without accessing the platform. The read consults the second table to find the hash value corresponding to the virtual disk offset of the block. The hash value is a key into the first table to find the block cache data offset of the data; the data is read from the cache.