Servicing file restorations in a deduplication filesystem using multiple read-ahead caches

A system comprising:

• a processor;
• and memory configured to store one or more sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of:
• provisioning access object (AOB) and deduplication object (DOB) services of a deduplication filesystem across a cluster of nodes;
• receiving, at a client-side library, a request to restore a file, the file being divided into chunks and the chunks being assigned to similarity groups;
• creating a first table mapping offset ranges in the file to the AOB services;
• issuing prefetch requests to the AOB services, according to the first table, for chunks of the file corresponding to the offset ranges;
• upon the AOB services receiving the prefetch requests, consulting a second table mapping the similarity groups to the DOB services, each DOB service being responsible for reading a chunk of an assigned similarity group from a storage layer of the filesystem;
• opening multiple internal read-ahead streams from the AOB services to the DOB services according to the second table, wherein the internal read-ahead streams prefetch the chunks read by the DOB services to populate read-ahead caches maintained at the AOB services;
• and
• servicing the request using the read-ahead caches.

A computer program product, comprising a non-transitory computer-readable medium having a computer-readable program code embodied therein, the computer-readable program code adapted to be executed by one or more processors to implement a method comprising:

• provisioning access object (AOB) and deduplication object (DOB) services of a deduplication filesystem across a cluster of nodes;
• receiving, at a client-side library, a request to restore a file, the file being divided into chunks and the chunks being assigned to similarity groups;
• creating a first table mapping offset ranges in the file to the AOB services;
• issuing prefetch requests to the AOB services, according to the first table, for chunks of the file corresponding to the offset ranges;
• upon the AOB services receiving the prefetch requests, consulting a second table mapping the similarity groups to the DOB services, each DOB service being responsible for reading a chunk of an assigned similarity group from a storage layer of the filesystem;
• opening multiple internal read-ahead streams from the AOB services to the DOB services according to the second table, wherein the internal read-ahead streams prefetch the chunks read by the DOB services to populate read-ahead caches maintained at the AOB services;
• and
• servicing the request using the read-ahead caches.