From owner-freebsd-questions@freebsd.org Fri Dec 8 22:46:01 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 0CAF9E913BD for ; Fri, 8 Dec 2017 22:46:01 +0000 (UTC) (envelope-from mike@sentex.net) Received: from smarthost2.sentex.ca (smarthost2.sentex.ca [IPv6:2607:f3e0:80:80::2]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client CN "smarthost.sentex.ca", Issuer "smarthost.sentex.ca" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id CDAD867E68 for ; Fri, 8 Dec 2017 22:46:00 +0000 (UTC) (envelope-from mike@sentex.net) Received: from lava.sentex.ca (lava.sentex.ca [IPv6:2607:f3e0:0:5::11]) by smarthost2.sentex.ca (8.15.2/8.15.2) with ESMTPS id vB8MjxcK022362 (version=TLSv1 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Fri, 8 Dec 2017 17:45:59 -0500 (EST) (envelope-from mike@sentex.net) Received: from [192.168.43.26] (saphire3.sentex.ca [192.168.43.26]) by lava.sentex.ca (8.15.2/8.15.2) with ESMTP id vB8MjvKU046898; Fri, 8 Dec 2017 17:45:57 -0500 (EST) (envelope-from mike@sentex.net) Subject: Re: zfs mirror and unequal writes To: Adam Vande More Cc: freebsd-questions References: From: Mike Tancsa Organization: Sentex Communications Message-ID: <6f2e4f4b-a320-7317-875b-d0e7df64a5b3@sentex.net> Date: Fri, 8 Dec 2017 17:45:56 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 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 22:46:01 -0000 On 12/8/2017 5:40 PM, Adam Vande More wrote: > > 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. Actually, thats the odd thing, swap is on ada0 (only) and its the one with dramatically less writes. I looked a few recently deployed SSD boxes and they are all very close as well. This is the one outlier. Not sure if its indicative of some other pathology of the drive ? 0{backup4}# grep swap /etc/fstab /dev/ada0p2 none swap sw 0 0 #/dev/ada1p2 none swap sw 0 0 0{backup4}# ls -l /etc/fstab -rw-r--r-- 1 root wheel uarch 111 Oct 24 2014 /etc/fstab 0{backup4}# 1{backup4}# gpart show ada0 => 34 250069613 ada0 GPT (119G) 34 6 - free - (3.0K) 40 1024 1 freebsd-boot (512K) 1064 41943040 2 freebsd-swap (20G) 41944104 208125536 3 freebsd-zfs (99G) 250069640 7 - free - (3.5K) 0{backup4}# gpart show ada1 => 34 250069613 ada1 GPT (119G) 34 6 - free - (3.0K) 40 1024 1 freebsd-boot (512K) 1064 41943040 2 freebsd-zfs (20G) 41944104 208125536 3 freebsd-zfs (99G) 250069640 7 - free - (3.5K) 0{backup4}# -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/