From owner-freebsd-current Sat Jan 31 13:28:14 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id NAA09577 for current-outgoing; Sat, 31 Jan 1998 13:28:14 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from tor-adm1.nbc.netcom.ca (taob@tor-adm1.nbc.netcom.ca [207.181.89.5]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id NAA09572 for ; Sat, 31 Jan 1998 13:28:12 -0800 (PST) (envelope-from taob@tor-adm1.nbc.netcom.ca) Received: (from taob@localhost) by tor-adm1.nbc.netcom.ca (8.8.5/8.8.5) id QAA12684; Sat, 31 Jan 1998 16:28:01 -0500 (EST) Date: Sat, 31 Jan 1998 16:28:00 -0500 (EST) From: Brian Tao X-Sender: taob@tor-adm1 To: Karl Denninger cc: current@FreeBSD.ORG Subject: Re: RAID controllers - folks, check this thing out In-Reply-To: <19980131144604.03410@mcs.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG X-To-Unsubscribe: mail to majordomo@FreeBSD.org "unsubscribe current" On Sat, 31 Jan 1998, Karl Denninger wrote: > > CCD mounted async is NOT a fair comparison - not at all. I note that in my message. Async mounts delay metainfo writes, and the RAID controller delays all writes to disk via its cache. It would be unfair to CCD, in that your chances of recovering a busy async filesystem after a crash are nearly zero. The comparison is useful when you consider that the CMD is almost able to keep up even without asynchronous updates. > Also, RAID 5 with other than 5 disks is sub-optimal, and some of those > tests were run with fewer drives. What is magic about having 5 drives? Obviously the more drives you add, the better the performance. I limited both RAID units to three drives to provide a more level comparison. These were done on eval units, and I would have liked six or more drives. -- Brian Tao (BT300, taob@netcom.ca) "Though this be madness, yet there is method in't"