This paper presents a new challenge-verifying that a remote server is storing a file in a fault-tolerant manner, i.e., such that it can survive hard-drive failures. We describe an approach called the Remote Assessment of Fault Tolerance (RAFT). The key technique in a RAFT is to measure the time taken for a server to respond to a read request for a collection of file blocks. The larger the number of hard drives across which a file is distributed, the faster the readrequest response. Erasure codes also play an important role in our solution. We describe a theoretical framework for RAFTs and offer experimental evidence that RAFTs can work in practice in several settings of interest.
RAFT REF can verify that a file is stored with sufficient redundancy by measuring the response time for accessing "well-collected" file blocks.
How to tell if your cloud files are vulnerable to drive crashes
CCS '11
Computer Science