From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756737Ab3AQU4Z (ORCPT ); Thu, 17 Jan 2013 15:56:25 -0500 Received: from mail.linux-iscsi.org ([67.23.28.174]:39572 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751814Ab3AQU4W (ORCPT ); Thu, 17 Jan 2013 15:56:22 -0500 Subject: Re: LIO - the broken iSCSI target implementation From: "Nicholas A. Bellinger" To: Andreas Steinmetz Cc: linux-kernel@vger.kernel.org, hch@infradead.org, torvalds@linux-foundation.org, target-devel In-Reply-To: <1358385543.7040.54.camel@host028-server-9.lan.domdv.de> References: <1358385543.7040.54.camel@host028-server-9.lan.domdv.de> Content-Type: text/plain; charset="UTF-8" Date: Thu, 17 Jan 2013 12:56:19 -0800 Message-ID: <1358456179.18551.34.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andreas, On Thu, 2013-01-17 at 02:19 +0100, Andreas Steinmetz wrote: > This is not a technical point of view. This is a more or less political > and user point of view. And for any replies, I'm not subscribed (haven't > been now for years). > > As a user, I was in need for an iSCSI target. Actually, I needed to > export a SAS tape device (Ultrium 5) - which is one of the devices still > sufficiently expensive to go the iSCSI target way) - well, not any disks > (cheap enough, NFS available) or CD/DVD writers (I'd call these penny > targets nowadays). > > Thus, lio (http://www.linux-iscsi.org/) seemed to be the politically and > technically favoured solution. Except: it simply doesn't work, userspace > utilities are seemingly not maintained, I'm not sure what you mean. There are targetcli+rtslib packages are available for virtually every distribution http://www.linux-iscsi.org/wiki/Targetcli#Linux_distributions > the web site is - simply put - > sales talk and when one tries to write manually to configfs the results > are kernel panics. Then your hitting a bug with pSCSI export with TYPE_TAPE. That's what your trying to do right..? > > A little bit more detail: > > Oh, well, maybe I do expect too much when a certain commercial > institution calls LIO "the standard open-source storage Target". Maybe > one should not expect typical hardware to be supported except, maybe, > when a commercial contract exists... > > Though the only chance to get the LIO target working for me was to try > to write hopefully proper values to configfs manually. Without any > usable documentation, that is. The result was: kernel panics (@hch: > don't ask me how to repeat - hire some apes hacking at LIO configfs, > that's whats required, apes need no documentation, either). > The full API reference for rtslib is available here: http://www.risingtidesystems.com/doc/rtslib-gpl/html/ As for targetcli, you'll want to use the in-line documenation available within the shell. http://www.linux-iscsi.org/wiki/Targetcli#Display_helphttp://www.linux-iscsi.org/wiki/Targetcli#Display_help > The fun part of it was that I finally ended up using SCST - which was > refrained from kernel inclusion for technical reasons beyond my > knowledge. What makes me prefer SCST is quite simple: > > It works, it is sufficiently documented and it is maintained. And, @hch: > Beautiful in kernel code first needs to work without producing kernel > panics (3.7.x) and it needs to be accompanied by working and > sufficiently documented user space utilities or, it needs to have a well > documented API (documentation needs to include a variety of examples, > not the old IBM way of simply documenting every flag without any > overview). > > As long as LIO userspace is a not maintained and instead seemingly a > sales playground and as long as LIO kernel code causes panics by simple > writes to configfs LIO seems to me worse than any alpha quality code. It > is simply useless. > Of course LIO userspace is maintained. If you find a bug, please report it to us so it can be addressed. Otherwise, I'm not sure what you expect to achieve by simply hand-waving. --nab