[svlug] Sync command slowdown

[Brian J. Tarricone]

Greg Lindahl wrote:

> sync is a big club: it syncs all the files in the system instead of
> just the ones you care about. And it can kill performance for other
> processes if there are a lot of pages to be written out.

Though, if you're using ext3, a whole-disk sync() and a single-file 
fsync() are sadly equivalent with certain (common?) journaling modes.

(See the not-so-recent Firefox 3 bug[1] relating to fsync() when 
committing various sqlite databases to disk.)

	-brian

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=421482