Method for populating a cache index on a deduplicated storage system

A method, article of manufacture, and apparatus for populating an index cache on a deduplicated storage system is discussed. A determination to flush an in-memory index to a hard drive (“HDD”) on the deduplicated storage system is made, wherein the in-memory index comprises in-memory hash buckets containing fingerprint identifiers and container identifiers. A first HDD index is loaded from the HDD into a memory, wherein the first index includes a plurality of HDD buckets. The fingerprint identifiers and the container identifiers are merged from the in-memory hash buckets into the HDD buckets. The HDD buckets are mapped to a plurality of solid state drive (“SSD”) buckets, the SSD buckets together comprising a SSD index. The fingerprint identifiers and container identifiers are inserted into the plurality of SSD buckets.