From owner-freebsd-arm@freebsd.org Sat Jan 21 17:58:18 2017 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 925C0CBB4A5 for ; Sat, 21 Jan 2017 17:58:18 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from outbound1a.eu.mailhop.org (outbound1a.eu.mailhop.org [52.58.109.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 3098D35B for ; Sat, 21 Jan 2017 17:58:17 +0000 (UTC) (envelope-from ian@freebsd.org) X-MHO-User: 2e7f14b9-e003-11e6-9357-bffcd86bd944 X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 73.78.92.27 X-Mail-Handler: DuoCircle Outbound SMTP Received: from ilsoft.org (unknown [73.78.92.27]) by outbound1.eu.mailhop.org (Halon) with ESMTPSA id 2e7f14b9-e003-11e6-9357-bffcd86bd944; Sat, 21 Jan 2017 17:58:16 +0000 (UTC) Received: from rev (rev [172.22.42.240]) by ilsoft.org (8.15.2/8.15.2) with ESMTP id v0LHw5dY006769; Sat, 21 Jan 2017 10:58:05 -0700 (MST) (envelope-from ian@freebsd.org) Message-ID: <1485021485.34897.185.camel@freebsd.org> Subject: Re: how to measure microsd wear From: Ian Lepore To: tech-lists , freebsd-arm@freebsd.org Date: Sat, 21 Jan 2017 10:58:05 -0700 In-Reply-To: <16821b7c-e300-97fc-36e5-a508b22c21b8@zyxst.net> References: <16821b7c-e300-97fc-36e5-a508b22c21b8@zyxst.net> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.18.5.1 FreeBSD GNOME Team Port Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Jan 2017 17:58:18 -0000 On Sat, 2017-01-21 at 15:46 +0000, tech-lists wrote: > Hello list, > > How would one measure microsd wear? Is there a utility like > smartmontools (I think this only works for regular hard drives) but > for > microsd? > > many thanks, There is basically no way to see what's going on in the flash array of an sdcard.  The microcontrollers in modern sd cards have complex wear- leveling algorithms which are completely transparent to the outside world. On the plus side, most of what you see in the way of warnings and scare stories about wearing out sd cards is pure BS.  I've got systems here that have been running for literally years on the same sdcard, and that card is being used for swap, and routine data storage like syslog (on an embedded system that logs status and progress pretty much continuously 24x7 for years).  I've seen a few sd cards die over the years, but I've never been able to say it was because of how much was written to them (indeed, the dead ones I've got weren't in service long before they died). -- Ian