Post data synchronization for domain migration

A method, performed by a target host device of a provider network, comprising:

• obtaining, by the target host device of the provider network, a read request directed to a migrating VM on the target host device, wherein the migrating VM on the target host device is being migrated from a source host device of the provider network;
• attempting to retrieve data associated with the read request from a local persistent storage of the target host device;
• determining that at least a portion of the data associated with the read request does not reside in the local persistent storage of the target host device;
• communicating with the source host device to retrieve at least the portion of the data associated with the read request from a local persistent storage of the source host device;
• and
• responding to the read request using at least the data portion from the local persistent storage of the source host device.

One or more non-transitory computer-readable storage media storing program instructions that when executed on or across one or more processors cause the one or more processors to implement a target host device on a provider network to:

• obtain a read request directed to a migrating VM on the target host device, wherein the migrating VM on the target host device is being migrated from a source host device of the provider network;
• attempt to retrieve data associated with the read request from a local persistent storage of the target host device;
• determine that at least a portion of the data associated with the read request does not reside in the local persistent storage of the target host device;
• communicate with the source host device to retrieve at least the portion of the data associated with the read request from a local persistent storage of the source host device;
• and
• respond to the read request using at least the data portion from the local persistent storage of the source host device.