From owner-freebsd-questions@freebsd.org Fri Dec 8 22:40:12 2017 Return-Path: Delivered-To: freebsd-questions@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 283FFE910A1 for ; Fri, 8 Dec 2017 22:40:12 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: from mail-it0-x230.google.com (mail-it0-x230.google.com [IPv6:2607:f8b0:4001:c0b::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id E3CD2678EF for ; Fri, 8 Dec 2017 22:40:11 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: by mail-it0-x230.google.com with SMTP id p139so7552030itb.1 for ; Fri, 08 Dec 2017 14:40:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=DiYTmGorOpCanp67Vw5+160D+5SCRCZ08JqOhI53H6g=; b=E6v1f47WjOfI1Ub8hdw+nD8u9A3eSUzKGrDWq+cwNwTZe4njBoN85W7vR8jNOJZ5mv cByTnsJHquenJqY9asadIErzfGsFkaI0+Fn3WPMq1/wh+A96l6oWLU4RiyV9I1kdFrD8 Zr2JEbtPrI1SlbQ5tsC3AhCG9qQaCcPby0LXOpjP34/PujOzLuTtEHB8KV+KfsW/+zxd wVRSgJAjIe3nl5Tz8vaOrDAHRIf0ZYtjrBnpcLC9jw6mb94ERZRmeQKVwuYv45FwqZNq up+VciBGkyIxgAXBswhyVMqoIxSrNadwZgghPdZ+S5yYozFN1lNppw2vcqByrg9eKXe/ NkGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=DiYTmGorOpCanp67Vw5+160D+5SCRCZ08JqOhI53H6g=; b=LcatxfK3H95zTWXjXsF+SrA/089r/UaK/y7qXcXb9JcatUKguYnsPDQhcHjK9UZ8IJ vBhVv88bbVjDm2Rq4cNZGnlVd4OT4cNDgrBiL35RqepoOTz6x5m6z1m11bm7jk7e6/uT fZhc6SOQNMDCg81llqU5vyhK2mQr6Ufq2YVbGMq9agceaJvnJFVwh20l1VZkvdKIuvP1 Wq3jWMlYCPJ2yuvw6OHuqdHrbdowIBOQfDf71dxUg0jwLaR55pmW6x+z099p4OHlB6OY 4LTCbJx9OYuEJu8cCWASI5rO3B3A+mqba5seDiojc3Xhekx1rk0O3FUC2CLhhjArFngy 8Lkw== X-Gm-Message-State: AKGB3mLDuPMBVBnF37xNWSSCDxHdPfwcF20jvRVHUdc894V/UYZtYacW q1Lr1HHlVrM4KMC7d9yEUsOVTH3IBZoFyo8YwxI= X-Google-Smtp-Source: AGs4zMaSMLZtcQ49ds3Rlbcc7B5HNPy+qDoamVpM1Laxg20BmYlST0igyI3cvdr+Staq33nvTBH3yzd8/4dZ/S7FZkc= X-Received: by 10.36.103.213 with SMTP id u204mr7580175itc.91.1512772811007; Fri, 08 Dec 2017 14:40:11 -0800 (PST) MIME-Version: 1.0 Received: by 10.2.138.114 with HTTP; Fri, 8 Dec 2017 14:40:10 -0800 (PST) In-Reply-To: References: From: Adam Vande More Date: Fri, 8 Dec 2017 16:40:10 -0600 Message-ID: Subject: Re: zfs mirror and unequal writes To: Mike Tancsa Cc: freebsd-questions Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 08 Dec 2017 22:40:12 -0000 On Fri, Dec 8, 2017 at 3:57 PM, Mike Tancsa wrote: > I was reading up on SSD life spans and decided to take a quick look at > how many TBW my disks have gone through. Looking at one box I was really > surprised at the uneven amount of data written > > > 0{backup4}# smartctl -a /dev/ada0 | grep LBAs > 241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always > - 21004341355 > 0{backup4}# smartctl -a /dev/ada1 | grep LBAs > 241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always > - 413475182465 > 0{backup4}# > > I was quite surprised that there were WAY more writes to one disk that > the other. Give these are zfs mirrors, one says 192TB writes and the > other is 10TB ?!?!?! > > They were installed at the same time > Do you have the disks allocated in any other way eg swap or have a member drop out for awhile? I checked my mirror which has been in place for ~4 years and the values are pretty close, although I have different drives which are mechanical. -- Adam