From owner-freebsd-current@FreeBSD.ORG Thu Jul 3 09:35:56 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 81F2FB85 for ; Thu, 3 Jul 2014 09:35:56 +0000 (UTC) Received: from mail-vc0-x22e.google.com (mail-vc0-x22e.google.com [IPv6:2607:f8b0:400c:c03::22e]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 3AD112096 for ; Thu, 3 Jul 2014 09:35:56 +0000 (UTC) Received: by mail-vc0-f174.google.com with SMTP id hy4so11379547vcb.33 for ; Thu, 03 Jul 2014 02:35:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=DvfOOJY9Eawn/+f6L6/S712BcejlrL/oBBf4YT847ZY=; b=0T7trUn5xgpeeYFirvP6Frf7jVgLxhyln/wky7ZV5dzdWFYGaVHMn8AV2AVm7pvGZl ejT4d0g3yspbWmZzFEF+W8VHwtZ558e/BQySxVYE7rX/h/uGjQTps9oOYG0XnnvJc6pP 0ZLb4QgDw42fbd1My2Lcw5BOyazHhnJhrXHTnVaDlq+MYGd2K3/fEA1flHmqgaeO46Fv hPLg/IjRBHAoZau9QbtBiaD4uTRGWQkLWvF6IkxAmSxfSzXgmPVOYNunWAaFHY5SKjnl 4sf8VZHCcX6malxHUYIAjHTQ+6lxBATux0opPfhFlCvIOku6tCpjTU7Xax5Egcw9970f EcEw== MIME-Version: 1.0 X-Received: by 10.52.252.226 with SMTP id zv2mr2273794vdc.19.1404380155254; Thu, 03 Jul 2014 02:35:55 -0700 (PDT) Received: by 10.220.136.74 with HTTP; Thu, 3 Jul 2014 02:35:55 -0700 (PDT) In-Reply-To: <20140703091321.GP5102@zxy.spb.ru> References: <20140701091252.GB3443@brick> <20140701231305.GA37246@zxy.spb.ru> <20140702112609.GA85758@zxy.spb.ru> <20140702203603.GO5102@zxy.spb.ru> <20140703091321.GP5102@zxy.spb.ru> Date: Thu, 3 Jul 2014 10:35:55 +0100 Message-ID: Subject: Re: FreeBSD iscsi target From: Nikolay Denev To: Slawa Olhovchenkov Content-Type: text/plain; charset=UTF-8 Cc: Kevin Oberman , Sreenivasa Honnur , FreeBSD Current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Jul 2014 09:35:56 -0000 On Thu, Jul 3, 2014 at 10:13 AM, Slawa Olhovchenkov wrote: > On Thu, Jul 03, 2014 at 09:31:45AM +0100, Nikolay Denev wrote: > >> On Thu, Jul 3, 2014 at 12:06 AM, Kevin Oberman wrote: >> > On Wed, Jul 2, 2014 at 1:36 PM, Slawa Olhovchenkov wrote: >> > >> >> On Wed, Jul 02, 2014 at 12:51:59PM -0700, Kevin Oberman wrote: >> >> >> >> > On Wed, Jul 2, 2014 at 4:26 AM, Slawa Olhovchenkov >> >> wrote: >> >> > >> >> > > On Tue, Jul 01, 2014 at 10:43:08PM -0700, Kevin Oberman wrote: >> >> > > >> >> > > > On Tue, Jul 1, 2014 at 4:13 PM, Slawa Olhovchenkov >> >> > > wrote: >> >> > > > >> >> > > > > On Tue, Jul 01, 2014 at 11:12:52AM +0200, Edward Tomasz Napierala >> >> > > wrote: >> >> > > > > >> >> > > > > > Hi. I've replied in private, but just for the record: >> >> > > > > > >> >> > > > > > On 0627T0927, Sreenivasa Honnur wrote: >> >> > > > > > > Does freebsd iscsi target supports: >> >> > > > > > > 1. ACL (access control lists) >> >> > > > > > >> >> > > > > > In 10-STABLE there is a way to control access based on initiator >> >> > > > > > name and IP address. >> >> > > > > > >> >> > > > > > > 2. iSNS >> >> > > > > > >> >> > > > > > No; it's one of the iSCSI features that seem to only be used >> >> > > > > > for marketing purposes :-) >> >> > > > > > >> >> > > > > > > 3. Multiple connections per session >> >> > > > > > >> >> > > > > > No; see above. >> >> > > > > >> >> > > > > I think this is help for 40G links. >> >> > > > > >> >> > > > >> >> > > > I assume that you are looking at transfer of large amounts of data >> >> over >> >> > > 40G >> >> > > > links. Assuming that tis is the case, yes, multiple connections per >> >> > > session >> >> > > >> >> > > Yes, this case. As I know, single transfer over 40G link limited by >> >> > > 10G. >> >> > > >> >> > ??? No, not at all. Getting 40G performance over TCP is not easy, but >> >> there >> >> > is no 10G limitation. >> >> >> >> As I know (may be wrong) 40G is bundled 4x10G link. >> >> For prevent packet reordering (when run over diferrent link) all >> >> packets from one sessoin must be routed to same link. >> >> Same issuse for Etherchannel. >> >> >> > >> > No, 40G Ethernet is single channel from the interface perspective.. What >> > my be confusing you is that they may use "lanes" which, for 40G, are >> > 10.3125G. But, unlike the case with Etherchannel, these lanes are "hidden" >> > from the MAC. The interface deals with a single stream and parcels it out >> > over the 10G (or 25G) lanes. All 100G optical links use multiple lanes >> > (4x25G or 10x10G), but 40G my use either a single 40G lane for distances of >> > up to 2km or 4x10G for longer runs. >> > >> > Since, in most cases, 40G is used within a data center or to connect to >> > wave gear for DWDM transmission over very long distances, most runs are >> > under 2km, so a single 40G lane may be used. When 4 lanes are used, a >> > ribbon cable is required to assure that all optical or copper paths are >> > exactly the same length. Since the PMD is designed to know about and use >> > these lanes for a single channel, the issue of packet re-ordering is not >> > present and the protocol layers above the physical are unaware of how many >> > lanes are used. >> > >> > Wikipedia has a fairly good discussion under the unfortunate title of 100 >> > Gigabit Ethernet . >> > Regardless of the title, the article covers both 40 and 100 Gigabit >> > specifications as both were specified on the same standard, 802.3ba. >> > >> > -- >> > R. Kevin Oberman, Network Engineer, Retired >> > E-mail: rkoberman@gmail.com >> > _______________________________________________ >> > freebsd-current@freebsd.org mailing list >> > http://lists.freebsd.org/mailman/listinfo/freebsd-current >> > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >> >> I found this white paper useful in understanding how this works : >> http://www.cisco.com/c/en/us/products/collateral/switches/nexus-3000-series-switches/white_paper_c11-726674.pdf > > In real world "Reality is quite different than it actually is". > http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-6500-series-switches/white_paper_c11-696669.html > > See "Packet Path Theory of Operation. Ingress Mode". > Interesting, however this seems like implementation specific detail, and not limitation of native 40Gbit ethernet. Still, it's something that one must be aware of (esp when dealing with Cisco gear :) ) I wonder why they are not doing something like this : http://blog.ipspace.net/2011/04/brocade-vcs-fabric-has-almost-perfect.html --Nikolay