Commands

set global innodb_disallow_writes=ON
set global innodb_disallow_writes=OFF

Purpose

These enable and disable all Innodb file system activity except for reads. If you want to take a database backup without stopping the server and you don't use LVM, ZFS or some other storage software that provides snapshots, then you can use this to halt all destructive file system activity from InnoDB and then backup the InnoDB data files. Note that it is not sufficient to run FLUSH TABLES WITH READ LOCK as there are background IO threads used by InnoDB that may still do IO.

5.0.37 Patch

Comment by burtonator, Sep 17, 2008

Any chance that you can accomplish a similar mechanism by setting innodb_max_dirty_pages_pct to zero and then waiting for dirty buffers to equal zero... then performing the snapshot (of course with a READ LOCK) on all the tables.

I generally think this patch is a bit more elegant though.

Kevin Burton (spinn3r.com)

Comment by arjen.lentz, Nov 02, 2008

Added to OurDelta? d7 patchset (contributed by David Stainton @ Spinn3r)

Comment by yukunming668, Dec 02, 2008

就

Comment by dimitri....@gmail.com, Dec 30, 2008

Anyone ported this to 5.1 branch yet ???