From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: generating a Linux WWN? Date: Wed, 03 Oct 2007 10:59:47 -0400 Message-ID: <4703AE63.3010109@torque.net> References: <50432.44268.qm@web31802.mail.mud.yahoo.com> <47032C67.8080109@garzik.org> Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:44238 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754763AbXJCPAq (ORCPT ); Wed, 3 Oct 2007 11:00:46 -0400 In-Reply-To: <47032C67.8080109@garzik.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jeff Garzik Cc: ltuikov@yahoo.com, Michael Reed , James.Smart@Emulex.Com, linux-scsi Jeff Garzik wrote: > Luben Tuikov wrote: >> --- Jeff Garzik wrote: >>> The admin will have the option to auto-generate a WWN, should they so >>> desire. > >> What does that mean? "auto-generate"? By whom? > > The admin tells the kernel module to auto-generate a WWN, and the kernel > module happily obliges. > > The generation algorithm is whatever makes people happy. I would > probably pick a fixed prefix like 0x6C 0x69 0x63 ("lin"), something that > doesn't conflict with IEEE org ids for a long time to come. Then, > get_random_bytes() or hash some useful machine characteristics for the > rest of the bytes. > > >> What if they don't "auto-generate" (whatever that means)? > > Well, you either have a WWN or you don't :) Jeff, It is not quite black and white. As I tried to point out, when a SAS HBA is run in target mode, there is a good chance there aren't _enough_ unique SAS addresses allocated by the manufacturer. There should be naa-5 addresses for the ports, it is the target device address and 0 or more lu addresses that may need to be generated. Doug Gilbert