From owner-freebsd-scsi Fri Jun 20 03:37:30 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id DAA26217 for freebsd-scsi-outgoing; Fri, 20 Jun 1997 03:37:30 -0700 (PDT) Received: from time.cdrom.com (root@time.cdrom.com [204.216.27.226]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id DAA26212; Fri, 20 Jun 1997 03:37:27 -0700 (PDT) Received: from time.cdrom.com (jkh@localhost.cdrom.com [127.0.0.1]) by time.cdrom.com (8.8.5/8.6.9) with ESMTP id DAA27550; Fri, 20 Jun 1997 03:37:07 -0700 (PDT) To: dg@root.com cc: Simon Shapiro , "Justin T. Gibbs" , FREEBSD-HACKERS , FREEBSD-SCSI , Brian Tao Subject: Re: Announcement: New DPT RAID Controller Driver Available In-reply-to: Your message of "Fri, 20 Jun 1997 02:29:50 PDT." <199706200929.CAA12213@implode.root.com> Date: Fri, 20 Jun 1997 03:37:07 -0700 Message-ID: <27545.866803027@time.cdrom.com> From: "Jordan K. Hubbard" Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > haven't had a single failure in that array since. All of our drives have > fairly well balanced spindles and don't vibrate all that much, and I've never > seen a reported seek failure or noticed any slowness. In my opinion, the all- Erm, I think the difference we're probably seeing with wcarchive is the fact that each drive bay doesn't hold more than 8 drives (most holding far fewer) and is independantly bolted to the rack. That probably provides pretty good vibration isolation, but undoubtedly also at a drive-to-housing cost ratio which would be unacceptable to the truly big RAID builder. I would also be suspicious of the cooling properties of a plastic drive enclosure (it seems like packing it in a mini-Igloo ice chest would be no worse to me ;-), but given a much different racking scenario, say 80 drives in a single free-standing rack, I'm more than willing to believe that vibration becomes a significant problem requiring creative solutions. If it were my fingers signing the P.O. on a true drive-array-from-hell, I'd probably favor the vendor providing the best combination of all-metal construction, air-flow, power supply quality and vibration isolation. Unless, of course, they had something like the AMES wind tunnel providing forced airflow past the drives, then I suppose the plastic sled construction wouldn't really matter much, would it? :-) Jordan