From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin Subject: Re: Fwd: Re: [Scst-devel] linuxcon 2010... Date: Wed, 18 Aug 2010 21:52:01 +0400 Message-ID: <4C6C1DC1.8090208@vlnb.net> References: <4C69653E.6050808@vlnb.net> <1282077040.16098.47.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.126.171]:60948 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752197Ab0HRRv6 (ORCPT ); Wed, 18 Aug 2010 13:51:58 -0400 In-Reply-To: <1282077040.16098.47.camel@mulgrave.site> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: scst-devel , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org James Bottomley, on 08/18/2010 12:30 AM wrote: >> 1. What don't you like in the transition path for users from STGT to >> SCST, which I proposed: >> >> - The only people which would be affected by replacing of STGT by SCST >> would be users of ibmvstgt. Other STGT users would not notice it at all. >> Thus, we should update ibmvstgt for SCST. If ibmvstgt updated for SCST, >> the update for its users would be just writing of a simple scstadmin's >> config file. >> >> - STGT doesn't have backend drivers, which SCST doesn't have, so >> there's nothing to worry here. At max, AIO support should be added to >> fileio_tgt. >> >> - STGT user space targets can use SCST backend via scst_local module. >> Scst_local module is ready and work very well. >> >> The result would be very clear without any obsolete mess. > > So does that get us up to being a drop in replacement? I think you're > saying that even with all of this, at least the VSCSI part will need > updating, so the answer seems to be "no". Sorry, I can't understand, "no" for which? For the whole transition path, or just until there is a patch for ibmvstgt to become ibmvscst? >> 4. Have you changed your opinion that a driver level multipath is >> forbidden in Linux and now you think that an iSCSI target with MC/S >> support is acceptable? > > no; I still think MCS is a pointless duplication of multipath that only > works for iSCSI. Then, does it mean that similarly as it was with open-iscsi, which had to remove MC/S support to be able to be accepted into the mainline, an iSCSI target can't go into mainline if it has MC/S? Thanks for answers, Vlad