[singron]

Without fsync, the dirty page can sit in RAM and not even be sent to the disk, so a battery backup for the disk wouldn't solve data loss.

[latch]

Right..but you leave fsync on in this case, no? This might be incompatible with the locking required by this server-process edition though (I guess, no clue). But more generally speaking, fsync=on with a proper raid controller gives massive performance boost (like orders of magnitude) while being relatively resilient to power loss.