... This may improve performance when an NFS or other network file-system, as the synchronous round-trips to the server be required to establish file locks are avoided. However, if multiple connections attempt to access the same database file when ... 

 ... this locking mechanism might not work correctly if the database file is kept on an NFS filesystem. This is because fcntl() file locking is broken on many NFS implementations. You should avoid putting SQLite database files on NFS if multiple ... 

2.1. Filesystems with broken or missing lock implementations  ... This is especially true of network filesystems and NFS in particular. If SQLite is used on a filesystem where the locking primitives contain bugs, and if two or more threads or processes try to access the same database at the ... 

 ... One should note that POSIX advisory locking is known to be buggy or even unimplemented on many NFS implementations (including recent versions of Mac OS X) and that there are reports of locking problems for network filesystems under Windows. Your ... 

9.1. Broken Locking Implementations  ... We have received reports of implementations of both Windows network filesystems and NFS in which locking was subtly broken. We can not verify these reports, but as locking is difficult to get right on a network filesystem we have no ...