You're at the mercy of the disk. The best you can do is assume that anyone who uses your application in production will have enterprise hardware, those (usuall

You're at the mercy of the disk. The best you can do is assume that anyone who uses your application in production will have enterprise hardware, those (usually) don't lie about fsync (consumer hdd's are somewhat likely to do this) I've also not yet run across a SSD that lies about fsync. The disappointing thing is that most filesystems also blindly assume this. Ext4 is somewhat robust by design but I've heard of atleast one time where a (very) cheap consumer harddisk trashed any filesystem on crash, including ZFS to the point of becoming unmountable.