Network-accessible data volume modification

A system comprising:

• a plurality of servers hosting at least a portion of a first data volume;
• and
• a system comprising a processor and memory, wherein the memory includes instructions that cause the system to:
• receive a request to modify the first data volume;
• cause the plurality of servers to allocate at least a portion of the plurality of servers to provision a second data volume responsive to the request;
• cause the second data volume to execute input/output (I/O) requests in place of the first data volume before all data chunks from the first data volume are stored on the second data volume;
• cause the second data volume to retrieve and store a plurality of the data chunks stored in the first data volume;
• receive a request from a host system for a first data chunk;
• determine that the first data chunk is not stored in the second data volume;
• and
• cause prioritization of a transfer of the first data chunk over a second data chunk in the plurality of data chunks.

A non-transitory computer-readable medium having stored thereon executable program code that directs one or more computing devices to perform operations when executed on the one or more computing devices, the operations comprising:

• receiving a request to modify the first data volume;
• causing an allocation of at least a portion of a server to provision a second data volume responsive to the request;
• causing the second data volume to execute input/output (I/O) requests in place of the first data volume after the provisioning of the second data volume;
• causing the second data volume to retrieve and store a plurality of data chunks stored in the first data volume;
• receiving a request for a first data chunk in the plurality of data chunks;
• and
• causing prioritization of a transfer of the first data chunk over a second data chunk in the plurality of data chunks responsive to a determination that the first data chunk is not stored in the second data volume.