Re: Regarding client fairness

["J. Bruce Fields" <bfields@fieldses.org>]

On Wed, Mar 28, 2018 at 06:35:53PM +0300, Antti Tönkyrä wrote:
> On 2018-03-28 17:59, J. Bruce Fields wrote:
> >On Wed, Mar 28, 2018 at 10:54:06AM -0400, bfields wrote:
> >>On Wed, Mar 28, 2018 at 02:04:57PM +0300, daedalus@pingtimeout.net wrote:
> >>>I came across a rather annoying issue where a single NFS client
> >>>caused resource starvation for NFS server. The server has several
> >>>storage pools which are used, in this particular case a single
> >>>client did fairly large read requests and effectively ate all nfsd
> >>>threads on the server and during that other clients were getting
> >>>hardly any I/O through to the other storage pool which was
> >>>completely idle.
> >>What version of the kernel are you running on your server?
> 4.15.10 on the system I am testing on.
> >I'm thinking that if it includes upstream 637600f3ffbf "SUNRPC: Change
> >TCP socket space reservation" (in upstream 4.8), then you may want to
> >experiment setting the sunrpc.svc_rpc_per_connection_limit module
> >parameter added in ff3ac5c3dc23 "SUNRPC: Add a server side
> >per-connection limit".
> >
> >You probably want to experiment with values greater than 0 (the default,
> >no limit) and the number of server threads.
> That helps for the client slowing down the whole server, thanks for
> the tip! Of course this doesn't help with the case of client
> accessing 2 different shares on the same server but that is
> something I can work around.

I thought the Linux client shared a single connection in that case, but
I could be wrong.

--b.