From owner-freebsd-virtualization@freebsd.org Thu Dec 22 10:14:05 2016 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C7659C8A75D for ; Thu, 22 Dec 2016 10:14:05 +0000 (UTC) (envelope-from bu7cher@yandex.ru) Received: from forward3o.cmail.yandex.net (forward3o.cmail.yandex.net [IPv6:2a02:6b8:0:1a72::288]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "forwards.mail.yandex.net", Issuer "Yandex CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7FE29184B for ; Thu, 22 Dec 2016 10:14:05 +0000 (UTC) (envelope-from bu7cher@yandex.ru) Received: from smtp1j.mail.yandex.net (smtp1j.mail.yandex.net [IPv6:2a02:6b8:0:801::ab]) by forward3o.cmail.yandex.net (Yandex) with ESMTP id 56FED20FAF; Thu, 22 Dec 2016 13:14:01 +0300 (MSK) Received: from smtp1j.mail.yandex.net (localhost.localdomain [127.0.0.1]) by smtp1j.mail.yandex.net (Yandex) with ESMTP id 9CD7A3C80F60; Thu, 22 Dec 2016 13:14:00 +0300 (MSK) Received: by smtp1j.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id mRDgGARMF5-Dx7OekE9; Thu, 22 Dec 2016 13:13:59 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1482401639; bh=daygi69Qp0dF9zZRISc08pQS3FV5+TaATmO1hgROPtk=; h=Subject:To:References:From:Message-ID:Date:In-Reply-To; b=Yfic3v50a2xSxTVLMcyZxX2ILj9BPxRsWPx4U4144dhqSWNrOWtawtFD4LfigmR85 FlloJVLjPWPrIMp2GExn++y5Zl1eVtRUkwa2I5K5YFb+xkSnT4dPK17SjxEpBIWFzs BIT9P+uaIkX2ZXggQzwpBVBuA+ZMieXFi875bPIc= Authentication-Results: smtp1j.mail.yandex.net; dkim=pass header.i=@yandex.ru X-Yandex-Suid-Status: 1 0,1 0 Subject: Re: Jumbo frames truncated at 4084 bytes by virtio-net? (using if_bridge(4) and vtnet(4) with mtu 9000) To: Harry Schmalzbauer , freebsd-virtualization@freebsd.org References: <585AA902.50907@omnilan.de> From: "Andrey V. Elsukov" Message-ID: <9b7951c0-9466-2b89-84de-c1026ee8f1c0@yandex.ru> Date: Thu, 22 Dec 2016 13:13:33 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <585AA902.50907@omnilan.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Dec 2016 10:14:05 -0000 On 21.12.2016 19:08, Harry Schmalzbauer wrote: > Hello, > > I'm having guest connectivity problems with jumbo frames. > > Since if_bridge(4) requires all interfaces to have the same MTU (and the > uplink interface also handles iscsi traffic, which greatly benefits from > jumbo frames), I > 'ifconfig create vmnet0 mtu 9000' > > Now my problem is that I can't simply keep guest's mtu at 1500, since > the host will send jumbo frames as answer wich never get through virtio-net. > > Does anybody have an idea how to fix/work arround? This looks like the problem with mbufs bigger than PAGE_SIZE. Do you see some denied requests in the `netstat -m` output? -- WBR, Andrey V. Elsukov