On Mon, Nov 4, 2013 at 12:26 PM, <m.roth at 5-cent.us> wrote: >>> >> I'm trying to make sense of that timing. Does that mean that >> pre-6.x, fsync() didn't really wait for the data to be written to >> disk, or does it somehow take 7 minutes to get 100M onto your disk in >> the right order? Or is this an artifact of a specific raid >> controller and what you have to do to flush its cache? > > No, this is regardless of what box, old Penguins, newer Dell's with PERC > 600 or 700 RAID controllers. Apparently, this "barrier" controls > journalling transactions, so that they are in order, or something like > that. I just don't see where that kind of time can go unless it is forcing a flush of a large (and probably mostly unrelated) cache to disk - possibly even in the internal drive caches if there is a way to do that, and waiting for it to complete after each file close. -- Les Mikesell lesmikesell at gmail.com