From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: From: erik quanstrom Date: Wed, 26 Dec 2007 08:10:05 -0500 To: 9fans@cse.psu.edu Subject: Re: [9fans] ata drive capabilities In-Reply-To: <13426df10712252231u167ae5c2k616534728b97e338@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: 223ba9b8-ead3-11e9-9d60-3106f5b1d025 On Wed Dec 26 01:33:14 EST 2007, rminnich@gmail.com wrote: > On Dec 25, 2007 6:59 PM, erik quanstrom wrote: > >(we have a drive > > in the lab that smart declares will fail any minute now. it's been > > this way for 2 years.) > > From everything I've seen, SMART has zero correlation with real > hardware issues -- confirmed by a discussion with someone at a big > search company. SMART is dumb. the google paper shows a 40% afr for the first 6 months after some smart errors appear. (unfortunately they don't do numbers for a simple smart status.) from my understanding of how google do things, loosing a drive just means they need to replace it. so it's cheeper to let drives fail. on the other hand, we have our main filesystem raided on an aoe appliance. suppose that one of those raids has two disks showing a smart status of "will fail". in this case i want to know the elevated risk and i will allocate a spare drive to replace at least one of the drives. i guess this is the long way of saying, it all depends on how painful loosing your data might be. if it's painful enough, even a poor tool like smart is better than nothing. - erik