From owner-freebsd-scsi Fri Apr 7 6:39:15 2000 Delivered-To: freebsd-scsi@freebsd.org Received: from worf.qntm.com (worf.qntm.com [146.174.250.100]) by hub.freebsd.org (Postfix) with ESMTP id 95ECB37BB55 for ; Fri, 7 Apr 2000 06:39:12 -0700 (PDT) (envelope-from Stephen.Byan@quantum.com) Received: from mail3.qntm.com by worf.qntm.com with ESMTP (1.40.112.12/16.2) id AA074444752; Fri, 7 Apr 2000 06:39:12 -0700 Received: from milcmimb.qntm.com (milcmimb.qntm.com [146.174.18.77]) by mail3.qntm.com (8.8.6/8.8.6) with ESMTP id GAA25348 for ; Fri, 7 Apr 2000 06:39:15 -0700 (PDT) Received: by milcmimb.qntm.com with Internet Mail Service (5.5.2650.10) id ; Fri, 7 Apr 2000 06:39:07 -0700 Message-Id: <8133266FE373D11190CD00805FA768BF02EE9F64@shrcmsg1.tdh.qntm.com> From: Stephen Byan To: freebsd-scsi@FreeBSD.ORG Subject: RE: newfs on IBM disks slower than Seagate disks? Date: Fri, 7 Apr 2000 06:39:01 -0700 Mime-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.10) Content-Type: text/plain; charset="iso-8859-1" Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Does the FreeBSD SCSI subsystem set the FUA bit in the CDB for UFS metadata writes? If so, then data integrity with WCE=1 is probably no worse than for WCE=0, since the filesystem is caching non-metadata writes anyway. If UFS and CAM haven't made arrangements to hint which disk writes are precious, then I think you're best off setting WCE=0, unless your system and your disks are on a UPS. Regards, -Steve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message