US Patent 11188463 Reduced downtime for a virtual machine content-based read cache

A system is described for enabling content-based read caching on a virtual machine without downtime for creating the digest file by launching the virtual machine before the digest file is produced and creating the digest file dynamically during runtime. After the virtual machine is executed, a background process creates the digest file in the background. The background process is paused during input/output operations and resumes when there are no pending input/output requests.