From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Use of WD20EARS with MDADM Date: Wed, 14 Apr 2010 15:53:43 -0400 Message-ID: <4BC61D47.6090403@tmr.com> References: <4BAB8D41.4010801@gmail.com> <4BABA12D.6040605@shiftmail.org> <4BAF8185.9040307@gmx.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4BAF8185.9040307@gmx.net> Sender: linux-raid-owner@vger.kernel.org To: st0ff@npl.de Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids 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? >>>> >>>> Note, they have 4K sectors. >>>> >>>> Thank you for your kind responses. >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe >>>> linux-raid" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>>> >>> This is a low-cost consumer disk that is rated for a whole 2400 hours >>> use in a year. You get what you pay for. >>> >> I think the "I" in RAID stands for inexpensive :-P >> Jokes apart, don't you think frequent scrubbing (e.g. weekly for a >> raid-6 or 2/week for raid-1/10) is enough to compensate for this? >> I would be way more concerned with ERC / TLER if it proves to be >> nonsettable, but I might be wrong >> > > Just for those who like to read: ERC is a feature stated in the > ATA-specifications, that's why the "quick hack" for smartctl was so > easy. But in the specs it is also noted, that the change a > SCT-ERC-Command does will not survive a power cycle. > > So y'all will probably need some udev-triggered daemon, which runs upon > connecting a disk, checking if this disk is conforming to the ata-spec, > then finding out if it's part of a raid array. If all answers yield > "yes", it should call SCT-ERC with a configurable value, and probably > some other "configure the drive"-commands (for tuning the idle timeout > of wdXXears). > > I'll have to think about that as a project again ... > I would think it was easier to just add a small section to rc.local, unless you antucipate lots of errors during boot and after udev gets going. -- Bill Davidsen "We can't solve today's problems by using the same thinking we used in creating them." - Einstein