VoltDB's web site shows that the community edition supports full ACID (which includes the D for durability) but it doesn't look like it supports the crash recovery which seems related to the command logging. Is there a different in the 'D' part of durability between the community edition and the commercial versions? If the machine goes down is all data lost?
The community edition has no disk durability. It has "durability" in the academic sense, that committed transactions won't be undone or rolled back by any subsequent work.
VoltDB doesn't really expect people to use the community edition in production where data can't be lost. The commercial edition supports live replication, synchronous disk persistence and multi-datacenter active-active replication.