Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964841AbYBHKho (ORCPT ); Fri, 8 Feb 2008 05:37:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932976AbYBHKhb (ORCPT ); Fri, 8 Feb 2008 05:37:31 -0500 Received: from mail-relay-01.mailcluster.net ([77.221.130.213]:48763 "EHLO mail-relay-01.mailcluster.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932945AbYBHKh3 (ORCPT ); Fri, 8 Feb 2008 05:37:29 -0500 Message-ID: <47AC30E8.6010205@vlnb.net> Date: Fri, 08 Feb 2008 13:37:28 +0300 From: Vladislav Bolkhovitin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.13) Gecko/20060501 Fedora/1.7.13-1.1.fc5 X-Accept-Language: en-us, ru, en MIME-Version: 1.0 To: david@lang.hm CC: Bart Van Assche , James Bottomley , "Nicholas A. Bellinger" , FUJITA Tomonori , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, scst-devel@lists.sourceforge.net, Andrew Morton , Linus Torvalds Subject: Re: Integration of SCST in the mainstream Linux kernel References: <1202144767.3096.38.camel@localhost.localdomain> <47A7488B.4080000@vlnb.net> <1202145901.3096.49.camel@localhost.localdomain> <47A751C5.60600@vlnb.net> <1202149322.3096.66.camel@localhost.localdomain> <47A75B8A.3020503@vlnb.net> <1202151293.3096.80.camel@localhost.localdomain> <47A8B210.8040202@vlnb.net> <1202238802.3133.71.camel@localhost.localdomain> <47AB0B63.20500@vlnb.net> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3405 Lines: 74 david@lang.hm wrote: > On Thu, 7 Feb 2008, Vladislav Bolkhovitin wrote: > >> Bart Van Assche wrote: >> >>> - It has been discussed which iSCSI target implementation should be in >>> the mainstream Linux kernel. There is no agreement on this subject >>> yet. The short-term options are as follows: >>> 1) Do not integrate any new iSCSI target implementation in the >>> mainstream Linux kernel. >>> 2) Add one of the existing in-kernel iSCSI target implementations to >>> the kernel, e.g. SCST or PyX/LIO. >>> 3) Create a new in-kernel iSCSI target implementation that combines >>> the advantages of the existing iSCSI kernel target implementations >>> (iETD, STGT, SCST and PyX/LIO). >>> >>> As an iSCSI user, I prefer option (3). The big question is whether the >>> various storage target authors agree with this ? >> >> >> I tend to agree with some important notes: >> >> 1. IET should be excluded from this list, iSCSI-SCST is IET updated >> for SCST framework with a lot of bugfixes and improvements. >> >> 2. I think, everybody will agree that Linux iSCSI target should work >> over some standard SCSI target framework. Hence the choice gets >> narrower: SCST vs STGT. I don't think there's a way for a dedicated >> iSCSI target (i.e. PyX/LIO) in the mainline, because of a lot of code >> duplication. Nicholas could decide to move to either existing >> framework (although, frankly, I don't think there's a possibility for >> in-kernel iSCSI target and user space SCSI target framework) and if he >> decide to go with SCST, I'll be glad to offer my help and support and >> wouldn't care if LIO-SCST eventually replaced iSCSI-SCST. The better >> one should win. > > > why should linux as an iSCSI target be limited to passthrough to a SCSI > device. > > the most common use of this sort of thing that I would see is to load up > a bunch of 1TB SATA drives in a commodity PC, run software RAID, and > then export the resulting volume to other servers via iSCSI. not a > 'real' SCSI device in sight. > > As far as how good a standard iSCSI is, at this point I don't think it > really matters. There are too many devices and manufacturers out there > that implement iSCSI as their storage protocol (from both sides, > offering storage to other systems, and using external storage). > Sometimes the best technology doesn't win, but Linux should be > interoperable with as much as possible and be ready to support the > winners and the loosers in technology options, for as long as anyone > chooses to use the old equipment (after all, we support things like > Arcnet networking, which lost to Ethernet many years ago) David, your question surprises me a lot. From where have you decided that SCST supports only pass-through backstorage? Does the RAM disk, which Bart has been using for performance tests, look like a SCSI device? SCST supports all backstorage types you can imagine and Linux kernel supports. > David Lang > - > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/