Andrew Morton wrote:

On Fri, 16 May 2008 14:02:46 -0500
Eric Sandeen [off-list ref] wrote:

quoted

A collection of patches to make ext3 & 4 use barriers by
default, and to call blkdev_issue_flush on fsync if they
are enabled.

Last time this came up lots of workloads slowed down by 30% so I
dropped the patches in horror.

I just don't think we can quietly go and slow everyone's machines down
by this much.  The overhead of journalling is already pretty horrid.

If we were seeing a significant number of "hey, my disk got wrecked"
reports which attributable to this then yes, perhaps we should change
the default.  But I've never seen _any_, although I've seen claims that
others have seen reports.

Here's a recent one, just FYI.

http://marc.info/?l=ext3-users&m=121205834608161&w=2

-Eric