Date:	Wed, 23 Jan 2008 20:11:34 +0300
From:	Vladislav Bolkhovitin <vst@...b.net>
To:	Bart Van Assche <bart.vanassche@...il.com>
CC:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	James.Bottomley@...senpartnership.com,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	linux-scsi@...r.kernel.org, scst-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: Re: Integration of SCST in the mainstream Linux kernel

Bart Van Assche wrote:
> As you probably know there is a trend in enterprise computing towards
> networked storage. This is illustrated by the emergence during the
> past few years of standards like SRP (SCSI RDMA Protocol), iSCSI
> (Internet SCSI) and iSER (iSCSI Extensions for RDMA). Two different
> pieces of software are necessary to make networked storage possible:
> initiator software and target software. As far as I know there exist
> three different SCSI target implementations for Linux:
> - The iSCSI Enterprise Target Daemon (IETD,
> http://iscsitarget.sourceforge.net/);
> - The Linux SCSI Target Framework (STGT, http://stgt.berlios.de/);
> - The Generic SCSI Target Middle Level for Linux project (SCST,
> http://scst.sourceforge.net/).
> Since I was wondering which SCSI target software would be best suited
> for an InfiniBand network, I started evaluating the STGT and SCST SCSI
> target implementations. Apparently the performance difference between
> STGT and SCST is small on 100 Mbit/s and 1 Gbit/s Ethernet networks,
> but the SCST target software outperforms the STGT software on an
> InfiniBand network. See also the following thread for the details:
> http://sourceforge.net/mailarchive/forum.php?thread_name=e2e108260801170127w2937b2afg9bef324efa945e43%40mail.gmail.com&forum_name=scst-devel.
> 
> About the design of the SCST software: while one of the goals of the
> STGT project was to keep the in-kernel code minimal, the SCST project
> implements the whole SCSI target in kernel space. SCST is implemented
> as a set of new kernel modules, only minimal changes to the existing
> kernel are necessary before the SCST kernel modules can be used. This
> is the same approach that will be followed in the very near future in
> the OpenSolaris kernel (see also
> http://opensolaris.org/os/project/comstar/). More information about
> the design of SCST can be found here:
> http://scst.sourceforge.net/doc/scst_pg.html.
> 
> My impression is that both the STGT and SCST projects are well
> designed, well maintained and have a considerable user base. According
> to the SCST maintainer (Vladislav Bolkhovitin), SCST is superior to
> STGT with respect to features, performance, maturity, stability, and
> number of existing target drivers. Unfortunately the SCST kernel code
> lives outside the kernel tree, which makes SCST harder to use than
> STGT.
> 
> As an SCST user, I would like to see the SCST kernel code integrated
> in the mainstream kernel because of its excellent performance on an
> InfiniBand network. Since the SCST project comprises about 14 KLOC,
> reviewing the SCST code will take considerable time. Who will do this
> reviewing work ? And with regard to the comments made by the
> reviewers: Vladislav, do you have the time to carry out the
> modifications requested by the reviewers ? I expect a.o. that
> reviewers will ask to move SCST's configuration pseudofiles from
> procfs to sysfs.

Sure, I do, although I personally don't see much sense in such move.

> Bart Van Assche.
> -
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@...r.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@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists