Data storage verification in distributed storage system

A server system, comprising:

• one or more processors;
• and
• memory storing one or more programs to be executed by the one or more processors, the one or more programs comprising instructions for:
• sending a verification request, to a first client device, to verify that the first client device is storing a data block on behalf of a second client device, the verification request including one or more verification parameters to be used by the first client device in computing a first verification value for the data block, wherein:
• the first client device leases memory space for storing data to one or more other client devices, including the second client device;
• and
• the first client device has a storage rating, which is used by the second client device to determine if the first client device satisfies storage criteria for storing data of the second client device;
• in response to the verification request, obtaining, from the first client device, the first verification value for the data block, wherein the first verification value is computed by the first client device based on the data block and the one or more verification parameters;
• comparing the first verification value with a second verification value for the data block, wherein the second verification value was previously computed, in accordance with the data block and the one or more verification parameters, and stored by the server system;
• in accordance with a determination that the first verification value matches the second verification value, confirming that the first client device is storing the data block;
• and
• in accordance with a determination that the first verification value does not match the second verification value, reducing the storage rating associated with the first client device.

A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions which, when executed by a server system with one or more processors, cause the server system to perform operations comprising:

• sending a verification request, from the server system to a first client device, to verify that the first client device is storing a data block on behalf of a second client device, the verification request including one or more verification parameters to be used by the first client device in computing a first verification value for the data block, wherein:
• the first client device leases memory space for storing data to one or more other client devices, including the second client device;
• and
• the first client device has a storage rating, which is used by the second client device to determine if the first client device satisfies storage criteria for storing data of the second client device;
• in response to the verification request, obtaining, from the first client device, the first verification value for the data block, wherein the first verification value is computed by the first client device based on the data block and the one or more verification parameters;
• comparing the first verification value with a second verification value for the data block, wherein the second verification value was previously computed, in accordance with the data block and the one or more verification parameters, and stored by the server system;
• in accordance with a determination that the first verification value matches the second verification value, confirming that the first client device is storing the data block;
• and
• in accordance with a determination that the first verification value does not match the second verification value, reducing the storage rating associated with the first client device.

A server system, comprising:

• means for sending a verification request to a first client device to verify that the first client device is storing a data block on behalf of a second client device, the verification request including one or more verification parameters to be used by the first client device in computing a first verification value for the data block, wherein:
• the first client device leases memory space for storing data to one or more other client devices, including the second client device;
• and
• the first client device has a storage rating, which is used by the second client device to determine if the first client device satisfies storage criteria for storing data of the second client device;
• means for obtaining from the first client device, in response to the verification request, the first verification value for the data block, wherein the first verification value is computed by the first client device based on the data block and the one or more verification parameters;
• means for comparing the first verification value with a second verification value for the data block, wherein the second verification value was previously computed, in accordance with the data block and the one or more verification parameters, and stored by the server system;
• means, enabled in accordance with a determination that the first verification value matches the second verification value, for confirming that the first client device is storing the data block;
• and
• means, enabled in accordance with a determination that the first verification value does not match the second verification value, for reducing the storage rating associated with the first client device.