process shared robust mutexes for tdb

[Ira Cooper]

On Mon, Mar 25, 2013 at 10:02 AM, Volker Lendecke <Volker.Lendecke at sernet.de
> wrote:

> On Mon, Mar 25, 2013 at 08:36:39AM -0400, Ira Cooper wrote:
> > On Fri, Mar 22, 2013 at 12:10 PM, Volker Lendecke <
> Volker.Lendecke at sernet.de
> > > wrote:
> >
> > > On Sat, Jan 12, 2013 at 10:45:57AM +0100, Volker Lendecke wrote:
> > > > Hi!
> > > >
> > > > On Sun, Jan 06, 2013 at 07:18:00PM -0500, Ira Cooper wrote:
> > > > > Can you run the same test with 1 bucket?  Not that we'd actually
> want
> > > to
> > > > > deploy that way, but, the performance of fcntl TDB shouldn't drop
> that
> > > > > much... and it'd give us an estimate of how much we need the 2048
> > > locks vs.
> > > > > just using 1.
> > > >
> > > > Under the usual branch
> > > >
> > > >
> https://git.samba.org/?p=vl/samba.git/.git;a=shortlog;h=refs/heads/tdb
> > > >
> > > > Now find a patchset that survived autobuild for me. It
> > > > contains some additional stuff, like a tdb feature flags
> > > > field. This could for example take a flag for a dual-linked
> > > > freelist and other future improvements.
> > > >
> > > > This is something that I would like to see broader testing
> > > > and review of. Getting rid of the fcntl locks in tdb was
> > > > something I have wanted to do for a very long time, and
> > > > while this is not complete it is a start in that direction.
> > >
> > > The above branch now contains code that has survived testing
> > > in a cluster with thousands of clients. The cluster survived
> > > a recovery just fine, something which was entirely
> > > impossible due to the fcntl thundering herd before. The fact
> > > that unmodified ctdb is happy with it shows that the API is
> > > covered pretty completely.
> > >
> > > I squashed all the patches into one. In the end, I had
> > > almost 100 unsorted patches, no way to sort them into a sane
> > > order.
> > >
> > > Comments?
> > >
> >
> > Looks good from a "review" point of view.  I have some work to do on the
> > "OS" side to support this patch, then I'd like to test it in our lab,
> > before giving the "all clear."
> >
> > Are you looking to have these patches pushed "as is", or looking for more
> > feedback before a final round?
>
> As metze wrote, the tdb piece to me is pretty complete, the
> libreplace patches need work. The tdb code has seen some
> heavy cluster testing within 3.6 and ctdb from the 1.2.40
> branch, but only on Linux. Testing on Solaris would be very
> much appreciated. It's not very much code, but it is so
> central that I am very cautious about it.
>
>
I'll see what I can do.  It is on my "to do list."

Thanks,

-Ira