From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Use of WD20EARS with MDADM Date: Wed, 21 Apr 2010 09:20:25 -0400 Message-ID: <4BCEFB99.9080806@tmr.com> References: <4BAB8D41.4010801@gmail.com> <4BABA12D.6040605@shiftmail.org> <4BAF8185.9040307@gmx.net> <4BC61D47.6090403@tmr.com> <4BCC65EB.3080803@cfl.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4BCC65EB.3080803@cfl.rr.com> Sender: linux-raid-owner@vger.kernel.org To: Phillip Susi Cc: st0ff@npl.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids Phillip Susi wrote: > On 4/14/2010 3:53 PM, Bill Davidsen wrote: > >> Stefan *St0fF* Huebner wrote: >> >>> Am 25.03.2010 18:45, schrieb Asdo: >>> >>> >>>> David Lethe wrote: >>>> >>>> >>>>> On Mar 25, 2010, at 11:20 AM, Andrew Dunn wrote: >>>>> >>>>> >>>>> >>>>>> Recently Dell is selling their WD20EARS (2TB) for 90$ >>>>>> >>>>>> This being one of the best PPG (Price Per Gigabyte) snatches I have >>>>>> seen, I was considering buying 8 of them for an mdadm array. >>>>>> >>>>>> Has anyone had experience with these drives? >>>>>> > > I believe that these disks only come in the "green" variety. I recently > picked up a 1.5 tb version for testing and cheap bulk storage, and I > would not suggest using them in a raid array because the green drives > firmware automatically parks the head after 8 seconds of inactivity and > reduces the rpm of the disk. The constant parking can quickly wear out > the head under high use and there is no way to disable this "feature". > I hear this said, but I don't have any data to back it up. Drive vendors aren't stupid, so if the parking feature is likely to cause premature failures under warranty, I would expect that the feature would not be there, or that the drive would be made more robust. Maybe I have too much faith in greed as a design goal, but I have to wonder if load cycles are as destructive as seems to be the assumption. I'd love to find some real data, anecdotal stories about older drives are not overly helpful. Clearly there is a trade-off between energy saving, response, and durability, I just don't have any data from a large population of new (green) drives. -- Bill Davidsen "We can't solve today's problems by using the same thinking we used in creating them." - Einstein