Aerospike - fast or safe?

Let's look at https://github.com/aerospike/aerospike-server/blob/180ed47a5fffc54b3e45faccb33c908bc189db2e/as/src/storage/drv_ssd.c and try to find open() system call and fsync() system call. We see that open flags like O_SYNC are parametrized. There is also loop for fsync with parametrized sleep time. Relevant configuration (https://github.com/aerospike/aerospike-server/blob/master/as/src/base/cfg.c) lives in enable-osync and fsync-max-sec. Now, check default values at http://www.aerospike.com/docs/reference/configuration/. We see that synchronous writes are disabled by default, and fsync is also disabled. This means that there are no safety guaranties for single Aerospike node (see also: flush-max-ms). Due to asd/OS/storage crash data will likely be lost or corrupted. Probabilistic situation for 3 nodes on different racks with battery backed SSD array is quite different and the combined risk is very small (if we do not consider whole datacenter crash) and therefore Aerospike is acceptable solution with standard sane data safety/integrity/availability criteria.