From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clay Haapala Subject: Re: Request for review of Linux iSCSI driver version 4.0.0.1 Date: Wed, 03 Dec 2003 16:32:14 -0600 Sender: linux-scsi-owner@vger.kernel.org Message-ID: References: <20031203221508.51C9B5DC7E@bambi.visi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from sj-iport-5.cisco.com ([171.68.10.87]:44814 "EHLO sj-iport-5.cisco.com") by vger.kernel.org with ESMTP id S262074AbTLCWcT (ORCPT ); Wed, 3 Dec 2003 17:32:19 -0500 In-Reply-To: <20031203221508.51C9B5DC7E@bambi.visi.com> (Scott M. Ferris's message of "Wed, 3 Dec 2003 16:15:08 -0600 (CST)") List-Id: linux-scsi@vger.kernel.org To: "Scott M. Ferris" Cc: James Bottomley , naveenb@cisco.com, Roman Zippel , hch@infradead.org, SCSI Mailing List , davmyers@cisco.com Thanks, Scott! On Wed, 3 Dec 2003, Scott M. Ferris uttered the following: > Clay Haapala wrote: >> >> A couple of related SCSI (not necessarily iSCSI) questions: >> >> "If the allowed count has not been exceeded" - The first two >> commands after a connection has been estabilished will fail with >> Unit_Attention. What if that first command then also gets a crc >> error (Aborted_command)? Will the retry count be large enough? > > The high-level driver picks the allowed count for each command, > which indicates how many times that command will be issued to the > low-level driver before being failed back to the high-level driver. > For disks, that's been 5 at least as far back as 2.2 kernels. > >> Does the retry also apply to tape? Without proper tape error >> recovery, retrying the command could result in duplicate records >> written to tape. > > The tape driver sets the allowed count to 0 for commands that change > the media, in order to disable any retries that would cause tape > positioning problems. Only commands like test unit ready and read > block limits get retries for tape. > > It would be a serious bug for the iSCSI driver to retry a command > with an allowed count of zero. -- Clay Haapala (chaapala@cisco.com) Cisco Systems SRBU +1 763-398-1056 6450 Wedgwood Rd, Suite 130 Maple Grove MN 55311 PGP: C89240AD Active dissent has been part of American government since the Boston Tea Party, and will be until its end.