On Mon, Nov 4, 2013 at 12:26 PM, <m.roth@xxxxxxxxx> 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@xxxxxxxxx
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