ftlog
The Upax log is an append-only file recording a series of commits. Each commit line contains at least a timestamp, the SHA3-256 hash of the file being committed, and the nodeID of the committer. It may also contain a POSIX path. The commit line is CR/LF-terminated. The hash is guaranteed to be unique to the file and the nodeID is unique to the committer. The path is not necessarily unique.
This is a chained log, meaning that the first line in each log file identifies the preceding log by its content hash. A copy of that log is present in the data store; on production systems this will normally be /var/Upax.
The expectation is that the Upax log will normally have two identical copies, one in memory and one on disk. The log specifies the state of the data store. All Upax servers in a cluster should share the same log, in the sense that all copies of the log should be identical.
Data stores may or may not be identical. A minimum number of servers (three if there are at least that many servers, all if fewer) must have a copy of a data file before it is committed.
