From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264833AbUGMKkY (ORCPT ); Tue, 13 Jul 2004 06:40:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264815AbUGMKkX (ORCPT ); Tue, 13 Jul 2004 06:40:23 -0400 Received: from web52510.mail.yahoo.com ([206.190.39.135]:36512 "HELO web52510.mail.yahoo.com") by vger.kernel.org with SMTP id S264826AbUGMKkG (ORCPT ); Tue, 13 Jul 2004 06:40:06 -0400 Message-ID: <20040713104002.10597.qmail@web52510.mail.yahoo.com> Date: Tue, 13 Jul 2004 03:40:02 -0700 (PDT) From: Shobhit Mathur Subject: SCSI Query - cmd_per_lun & can_queue ... To: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, I have a basic query related to the Scsi_Host_Template fields namely : cmd_per_lun and can_queue. I would like to know what is the relation between the per-lun queue and the per-HBA queue ? To elaborate my query, I would like to know how are the I/Os from the upper-layers managed between per-lun and the host-queue depth. In most cases the host-queue depth is very large [128 or more], while the per-lun queue is a fraction [5 or 2]. I would like to know how is the relation between the two queues and how does this impact io-rate ? - Kindly let me know as I have a blurred picture of the role of the 2 queues. - Thank you very much - Shobhit Mathur __________________________________ Do you Yahoo!? Yahoo! Mail - 50x more storage than other providers! http://promotions.yahoo.com/new_mail