[CentOS] unfsd scalability issues

[m.roth at 5-cent.us]

Boris Epstein wrote:
> On Sat, Jun 2, 2012 at 2:50 PM, John R. Dennison <jrd at gerdesas.com> wrote:
>> On Sat, Jun 02, 2012 at 10:59:13AM -0400, Boris Epstein wrote:
<snip>
> To be specific, I use UNFSD to export a MooseFS file system. MooseFS, by
> the way, is userland-process based too.
>
> Be that as it may, I've seen situations where a comparably configured
> MooseFS client get to read at, say, 40 MB/s - which is fine - but the
> UNFSD at the same time reads at 40K/s(!) Why would that be? I mean, some
> degradation I can dig but 3 orders of magnitude? What is with this? Am I
> doing something wrong?
<snip>
I wonder... what's the architecture of what you're getting these results?
I tried opening a bug with upstream over NFS4 and 6.x, and no one ever
looked at it, and they closed it.

100% repeatably: unpack a package locally, seconds.
                 unpack it from an NFS mount onto a local drive, about 1 min.
                 unpack it from an NFS mount onto an NFS mount, even when
                    the target is exported FROM THE SAME MACHINE* that the
                    process is running on: 6.5 - 7 MINUTES.

* That is,
     [server 1]                             [server 2]
        /export/thatdir --NFS-->    /target/dir
                                    /s2/source
                                    /source/dir --NFS-->/s2/source
     and cd [server 2]:/target/dir and unpack from /s2/source

I suppose I'll try logging into upstream's bugzilla using our official
licensed id; maybe then they'll assign someone to look at it....

        mark