From owner-freebsd-hackers@freebsd.org Thu Jul 5 18:01:10 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D7FC910434FB for ; Thu, 5 Jul 2018 18:01:10 +0000 (UTC) (envelope-from freebsd-rwg@pdx.rh.CN85.dnsmgr.net) Received: from pdx.rh.CN85.dnsmgr.net (br1.CN84in.dnsmgr.net [69.59.192.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 439E78D4F2; Thu, 5 Jul 2018 18:01:10 +0000 (UTC) (envelope-from freebsd-rwg@pdx.rh.CN85.dnsmgr.net) Received: from pdx.rh.CN85.dnsmgr.net (localhost [127.0.0.1]) by pdx.rh.CN85.dnsmgr.net (8.13.3/8.13.3) with ESMTP id w65I18nD048842; Thu, 5 Jul 2018 11:01:08 -0700 (PDT) (envelope-from freebsd-rwg@pdx.rh.CN85.dnsmgr.net) Received: (from freebsd-rwg@localhost) by pdx.rh.CN85.dnsmgr.net (8.13.3/8.13.3/Submit) id w65I18en048841; Thu, 5 Jul 2018 11:01:08 -0700 (PDT) (envelope-from freebsd-rwg) From: "Rodney W. Grimes" Message-Id: <201807051801.w65I18en048841@pdx.rh.CN85.dnsmgr.net> Subject: Re: Confusing smartd messages In-Reply-To: To: Stefan Blachmann Date: Thu, 5 Jul 2018 11:01:08 -0700 (PDT) CC: Wojciech Puchar , FreeBSD Hackers , George Mitchell , Lev Serebryakov X-Mailer: ELM [version 2.4ME+ PL121h (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Jul 2018 18:01:11 -0000 > Another problem issue is that flash memories also exhibit the charge > drain problem. > They cannot be read indefinitely without occasional rewrite, as every > read drains a minuscule amount of the charge. > > I often wished I knew of some OS/driver function/mechanism which can > rewrite respective refresh media on a mounted+running system and could > be, for example, run via cron. > > Such would not only be very useful to fix pending sectors without > stopping a running machine, but also for keeping embedded machines' > flash memories reliably charged over the years. It would be nice to have this feature, should not be too hard to implement just a matter of locking the device from start of read to end of write. > > On 7/5/18, Wojciech Puchar wrote: > >>> okay. What's the recommended action at this point? -- George > >> > >> In my experience it is begin of disk death, even if overall status is > >> PASSED. It could work for month or may be half a year after first > >> Offline_Uncorrectable is detected (it depends on load), but you best bet > >> to replace it ASAP and throw away. > > well my disk had this and live happily for 3 years. > > > > It JUST means that some sectors are unreadable which may be a reason that > > at some some write got wrong because of hardware problem. But this problem > > may be - and possibly were - powerdown while writing, or power spike. > > > > the media itself could be fine. the best action in such case is to force > > rewrite whole drive with some data. > > > > with gmirror it is as easy as first checking second drive for no errors, > > then forcing remirror. -- Rod Grimes rgrimes@freebsd.org