From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: storageworks controlers & linux-scsi Date: 27 Aug 2003 10:56:30 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1061999793.1660.8.camel@mulgrave> References: <1061816116.3f4a073487d64@impt3-1.free.fr> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from nat9.steeleye.com ([65.114.3.137]:5895 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S263450AbTH0P4i (ORCPT ); Wed, 27 Aug 2003 11:56:38 -0400 In-Reply-To: <1061816116.3f4a073487d64@impt3-1.free.fr> List-Id: linux-scsi@vger.kernel.org To: christophe.varoqui@free.fr Cc: SCSI Mailing List On Mon, 2003-08-25 at 07:55, christophe.varoqui@free.fr wrote: > In 2.4.21, a LUN hosted by a storageworks FC controler in multibus failover was > shown through 4 devices per HBA. 2 usable devices, 2 hang process that submit IO > in D-state. Such unusable devices, ghost paths, could be activated by sg_start. > > In current 2.4.22 pre-release and 2.6, only the valid path get presented though > associated sd are allocated and partialy setup. There is no longer a clear way > to start the ghosts as sg_utils will refuse to submit commands. This behaviour > is dicted by the new BLIST_NOSTARTONADD bflag. What's the inquiry strings of the array? That's what the BLIST_NOSTARTONADD flag uses. I'm curious to know why it even recognised the need not to start an array not in the black list. > I would like to know what was the intention of this patch (from steeleye I > guess) ? What problems does it solve ? > Wouldn't it be better to consider ghosts as removable media, as one would get > automatic activation on IO submition ? The intention of the patch is not to send spurious start commands to arrays as we boot up. The HP MSA/EVA storage gets very annoyed by this because a start triggers a path switch..you can imagine what this does to a SAN when lots of machines boot, since we try to start every visible path. The MSA/EVA seem to handle this fine and the switch over start command can be sent to the passive path on the event of active failure. James