On Wed, Oct 19, 2011 at 2:23 PM, Jay A. Kreibich <j...@kreibi.ch> wrote: > On Wed, Oct 19, 2011 at 02:13:35PM -0500, Nico Williams scratched on the wall: >> On Wed, Oct 19, 2011 at 4:00 AM, Stephan Beal <sgb...@googlemail.com> wrote: >> > On Tue, Oct 18, 2011 at 12:37 PM, Sune Ahlgren >> > <sune_ahlg...@hotmail.com>wrote: >> >> What can I do to make SQLite run safely on CIFS? >> > >> > Nothing. Even MS Access cannot (or could not way back when i used it) be >> > safely used on SMB/CIFS storage. >> >> Can you elaborate as to why? > > http://sqlite.org/faq.html#q5 > > > In short: buggy filesystem code that doesn't support distributed > locks correctly.
That explains why concurrent access over NFS or CIFS is dangerous. It doesn't explain that it's not possible to use SQLite3 over NFS or CIFS. Also, regarding NFS, it would be safe to use if SQLite3 were to use whole-file byte range locks. NFS makes concurrent access to byte ranges that are not locked unsafe. Of course, safely making changes to how SQLite3 locks files may be difficult now... CIFS does support byte range locking, and I suspect that the same rule I mentioned above regarding NFS applies. Plus, as a last resort there's CIFS open deny modes that SQLite3 could use to prevent concurrency. In response to other comments regarding other filesystems, I'll point out that on Lustre, because Lustre is fully POSIX-compliant regarding write visibility, SQLite3 should work fine as-is. Nico -- _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
