Restoring operation of data storage systems at disaster recovery sites

A computer program product for restoring operation of a data storage system at a disaster recovery site, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions readable and/or executable by a processor to cause the processor to:

• in response to a disaster event occurring at a primary site, receive, by the processor, an inode list from a cloud storage site, wherein the cloud storage site includes a backup copy of data that is stored at the primary site;
• receive, by the processor, configuration information from the cloud storage site;
• use, by the processor, the inode list and the configuration information to construct a filesystem at the disaster recovery site,
• wherein the filesystem at the disaster recovery site does not include a copy of the data that is stored at the primary site, wherein the filesystem includes a plurality of metadata stubs,
• wherein using the mode list and the configuration information to construct the filesystem at the disaster recovery site includes:
• performing a scale out backup and restore operation,
• wherein the scale out backup and restore operation includes causing a priority index process to scan a journal of the cloud storage site and metadata to determine which of the metadata to restore on a priority basis;
• restore, by the processor, the determined metadata according to the priority basis;
• and
• use, by the processor, the filesystem to satisfy input/output (I/O) commands that are received.

A system, comprising:

• a hardware processor;
• and
• logic integrated with the hardware processor, executable by the hardware processor, or integrated with and executable by the hardware processor, the logic being configured to:
• in response to a disaster event occurring at a primary site, receive, by the hardware processor, an inode list from a cloud storage site, wherein the cloud storage site includes a backup copy of data that is stored at the primary site;
• receive, by the hardware processor, configuration information from the cloud storage site;
• use, by the hardware processor, the inode list and the configuration information to construct a filesystem at a disaster recovery site,
• wherein the filesystem at the disaster recovery site does not include a copy of the data that is stored at the primary site, wherein the filesystem includes a plurality of metadata stubs,
• wherein using the inode list and the configuration information to construct the filesystem at the disaster recovery site includes:
• performing a scale out backup and restore operation;
• restore, by the hardware processor, metadata determined from the scale out backup and restore operation, wherein the determined metadata is restored according to a priority basis;
• and
• use, by the hardware processor, the filesystem to satisfy input/output (I/O) commands that are received.