From owner-freebsd-scsi@FreeBSD.ORG Tue Feb 28 09:23:39 2006 Return-Path: X-Original-To: freebsd-scsi@freebsd.org Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 94E5516A420 for ; Tue, 28 Feb 2006 09:23:39 +0000 (GMT) (envelope-from danny@cs.huji.ac.il) Received: from cs1.cs.huji.ac.il (cs1.cs.huji.ac.il [132.65.16.10]) by mx1.FreeBSD.org (Postfix) with ESMTP id BE50D43D78 for ; Tue, 28 Feb 2006 09:23:36 +0000 (GMT) (envelope-from danny@cs.huji.ac.il) Received: from pampa.cs.huji.ac.il ([132.65.80.32]) by cs1.cs.huji.ac.il with esmtp id 1FE14w-0001r7-QO; Tue, 28 Feb 2006 11:23:34 +0200 X-Mailer: exmh version 2.7.0 06/18/2004 with nmh-1.0.4 To: Tom Samplonius In-reply-to: Your message of Mon, 27 Feb 2006 22:53:07 -0800 (PST) . Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 28 Feb 2006 11:23:34 +0200 From: Danny Braniss Message-ID: Cc: freebsd-scsi@freebsd.org Subject: Re: Qlogic fibre channel support questions X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Feb 2006 09:23:39 -0000 > > On Mon, 27 Feb 2006, Matthew Jacob wrote: > > > Okay- let me ask why diskless booting doesn't work for you? > > Because NFS is slow. A locally disk (or a SAN attached disk, which is > essentially the same to FreeBSD) is going to be faster than NFS, no matter what. don't be too hasty with conclusions :-) 1- diskless: you can always boot diskless, then switch to 'real disk' in /etc/fstab: /dev/da0a / ufs rw 1 1 or what we do: /dev/da0b none swap sw /dev/da0d /var ufs rw 2 2 /dev/da0h /home ufs rw 2 2 so you don't have to boot from the SAN, but after loading the kernel (via 'slow' NFS) it will use the SAN. 2- as to speed, it all depends, specially on how deep are your pockets. i've been running several 'benchmarks' latetly and disk speed is not everything. sample: host is a Sun Fire X4200 (dual dula core Opteron) with SAS disks OS is FreeBSD 6.1-PRERELEASE amd64. make buildworld: diskless: 40m16.71s real 54m18.55s user 17m54.69s sys (using only 1 server*) nondiskless: 20m51.58s real 51m13.19s user 12m59.84s sys " but /usr/obj is iSCSI: 28m23.29s real 52m17.27s user 14m23.06s sys " but /usr/src and /usr/obj is iSCSI: 20m38.20s real 52m10.19s user 14m48.74s sys diskless but /usr/src and /usr/obj is iSCSI: 20m22.66s real 50m56.14s user 13m8.20s sys *: server in this case is a Xeon running in 64 mode but not very fast ethernet - em0 at 1gb but at about 50% efficiency. this server will 'make buildworld' in about 40 min. using the onboard LSILogic v3 MegaRAID RAID0. [iSCSI target is a Network Appliance] sorry for the noise, danny