From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Landman Subject: Re: Green drives and RAID arrays with partity Date: Sun, 25 Sep 2011 10:41:02 -0400 Message-ID: <4E7F3D7E.4070205@scalableinformatics.com> References: <4E7F0A31.4070001@yazzy.org> Reply-To: landman@scalableinformatics.com Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4E7F0A31.4070001@yazzy.org> Sender: linux-raid-owner@vger.kernel.org To: lists@yazzy.org Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 09/25/2011 07:02 AM, Marcin M. Jessa wrote: > Hi guys. > > I was wondering if it's safe to use so called green drives in RAID 5 = or > RAID 6 with md? You might need to turn off TLER and their power spin-down features, but= =20 in general, they *should* work ok. Modulo any firmware issues (staring= =20 intently at WD). We don't use Western Digital drives anymore due to ..= =2E=20 er ... profound high failure rates we've observed in the field. These=20 may or may not be connected to "greenness". They are definitely=20 connected to buggy firmware (this is on enterprise and consumer drives,= =20 used across a fairly wide swath of use cases). Your mileage may vary (e.g. you might have different experiences). We=20 wouldn't recommend them. > Drive such as Seagate Barracuda=AE Green 2TB ST2000DL003 or Western > Digital Caviar=AE Green=99 2TB WD20EARX have TLER off and reading mis= c > forums I understand that it would be a good idea to buy drives with t= hat > option available. TLER and the power spindown option are good things to be able to turn=20 off. Otherwise you need to have a way for the MD device to deal with a= =20 spun-down set of drives. I am not sure support is there for this right= =20 now ... I could be wrong, I've just not seen it. This said, spinning up and down drives is actually more stressful for=20 the electronics and motor. Better to leave them in one state whenever=20 possible. I can't remember the study I saw on this, but about a year=20 ago I saw a quietly published correlation between drive failures and=20 number of spinup/spindown cycles. My memory might be off on it, so fee= l=20 free to look for yourself (and don't rely upon my likely faulty memory)= =2E > On the other hand some people claim that Linux/Solaris/BSD based > software RAID may be able to work just fine with these drives. If the drives don't try to be "smart" and do "smart things" (powerdown,= =20 unlimited Herculean error recovery, massive sector remapping that takes= =20 it out of service for more than 60 seconds), yeah, they should "just=20 work". If you have a barrel full of these drives and need to use them,= =20 by all means, just turn off the "smart" features. OTOH, if you are buying new drives, steer clear of them. --=20 Joseph Landman, Ph.D =46ounder and CEO Scalable Informatics, Inc. email: landman@scalableinformatics.com web : http://scalableinformatics.com http://scalableinformatics.com/sicluster phone: +1 734 786 8423 x121 fax : +1 866 888 3112 cell : +1 734 612 4615 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html