From: "J. Bruce Fields" <bfields@fieldses.org>
To: "Antti Tönkyrä" <daedalus@pingtimeout.net>
Cc: linux-nfs@vger.kernel.org
Subject: Re: Regarding client fairness
Date: Wed, 28 Mar 2018 11:58:01 -0400 [thread overview]
Message-ID: <20180328155801.GA3354@fieldses.org> (raw)
In-Reply-To: <4abd5e4f-2992-730b-8d44-5e611a3a2451@pingtimeout.net>
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!
We should probably revisit 637600f3ffbf "SUNRPC: Change TCP socket space
reservation". There's got to be some way to keep high bandwidth pipes
filled with read data without introducing this problem where a single
client can tie up every server thread.
Just out of curiosity, do you know (approximately) the network and disk
bandwidth in this case?
--b.
next prev parent reply other threads:[~2018-03-28 15:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-28 11:04 Regarding client fairness daedalus
2018-03-28 14:54 ` J. Bruce Fields
2018-03-28 14:59 ` J. Bruce Fields
2018-03-28 15:35 ` Antti Tönkyrä
2018-03-28 15:47 ` J. Bruce Fields
2018-03-28 15:58 ` J. Bruce Fields [this message]
2018-03-28 16:49 ` Antti Tönkyrä
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