From owner-freebsd-questions@freebsd.org Mon Jan 21 12:35:41 2019 Return-Path: Delivered-To: freebsd-questions@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 7177D14A81E3 for ; Mon, 21 Jan 2019 12:35:41 +0000 (UTC) (envelope-from 4250.10.freebsd-questions=freebsd.org@email-od.com) Received: from s1-b0c6.socketlabs.email-od.com (s1-b0c6.socketlabs.email-od.com [142.0.176.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 7D54086E6D for ; Mon, 21 Jan 2019 12:35:40 +0000 (UTC) (envelope-from 4250.10.freebsd-questions=freebsd.org@email-od.com) DKIM-Signature: v=1; a=rsa-sha256; d=email-od.com;i=@email-od.com;s=dkim; c=relaxed/relaxed; q=dns/txt; t=1548074140; x=1550666140; h=content-transfer-encoding:content-type:mime-version:references:in-reply-to:message-id:subject:cc:to:from:date:x-thread-info; bh=43yAbcqIpJedZv3bCZOLsnPsZ/FJ7TzwETsSE4oy6X4=; b=X3MMr6OtGOgGdZfz+FZhi8BgGmqC5N52fNgL3HsQnwT0caRTB4oOeOA2BJl/WK+2d62SBW9NI0lBtpS02+v1mgCQ5k+aqLNgFagw8jHJTNCmS3BNYZ8+P3R6ADUacywg5p8b2F19vcm38qN0ja+ze3jqc9b53QZ1EHcr+3SxOQE= X-Thread-Info: NDI1MC4xMi4xYTMwMDAwMDBlOWZlNzUuZnJlZWJzZC1xdWVzdGlvbnM9ZnJlZWJzZC5vcmc= Received: from r5.us-west-2a.aws.in.socketlabs.com (r5.us-west-2a.aws.in.socketlabs.com [52.39.5.146]) by mxsg2.email-od.com with ESMTP(version=Tls12 cipher=Aes256 bits=256); Mon, 21 Jan 2019 07:35:29 -0500 Received: from smtp.lan.sohara.org (EMTPY [89.127.62.20]) by r5.us-west-2a.aws.in.socketlabs.com with ESMTP(version=Tls12 cipher=Aes256 bits=256); Mon, 21 Jan 2019 07:35:27 -0500 Received: from [192.168.63.1] (helo=steve.lan.sohara.org) by smtp.lan.sohara.org with smtp (Exim 4.91 (FreeBSD)) (envelope-from ) id 1glYnU-000HDL-Tn; Mon, 21 Jan 2019 12:35:24 +0000 Date: Mon, 21 Jan 2019 12:35:24 +0000 From: Steve O'Hara-Smith To: Yasuhiro KIMURA Cc: freebsd-questions@freebsd.org Subject: Re: Performance degradation of ZFS? Message-Id: <20190121123524.3c97bdfb2254e3393a58b831@sohara.org> In-Reply-To: <20190121.210941.2275299827563542964.yasu@utahime.org> References: <20190121.210941.2275299827563542964.yasu@utahime.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; amd64-portbld-freebsd12.0) X-Clacks-Overhead: "GNU Terry Pratchett" Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 7D54086E6D X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=pass header.d=email-od.com header.s=dkim header.b=X3MMr6Ot; spf=pass (mx1.freebsd.org: domain of 4250.10.freebsd-questions=freebsd.org@email-od.com designates 142.0.176.198 as permitted sender) smtp.mailfrom=4250.10.freebsd-questions=freebsd.org@email-od.com X-Spamd-Result: default: False [-1.75 / 15.00]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:142.0.176.0/20]; MV_CASE(0.50)[]; RCVD_COUNT_THREE(0.00)[4]; DKIM_TRACE(0.00)[email-od.com:+]; RCPT_COUNT_TWO(0.00)[2]; MX_GOOD(-0.01)[mxbh.socketlabs.com,mxbsg.socketlabs.com]; FORGED_SENDER(0.00)[steve@sohara.org,4250.10.freebsd-questions=freebsd.org@email-od.com]; SUBJECT_ENDS_QUESTION(1.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:7381, ipnet:142.0.176.0/22, country:US]; RCVD_TLS_LAST(0.00)[]; FROM_NEQ_ENVFROM(0.00)[steve@sohara.org,4250.10.freebsd-questions=freebsd.org@email-od.com]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.98)[-0.979,0]; R_DKIM_ALLOW(-0.20)[email-od.com:s=dkim]; MID_RHS_MATCH_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_SHORT(-0.54)[-0.539,0]; NEURAL_HAM_LONG(-0.99)[-0.992,0]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[sohara.org]; FORGED_SENDER_VERP_SRS(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[198.176.0.142.list.dnswl.org : 127.0.15.0]; ENVFROM_VERP(0.00)[]; IP_SCORE(-0.23)[ip: (-0.57), ipnet: 142.0.176.0/22(-0.28), asn: 7381(-0.22), country: US(-0.08)] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Jan 2019 12:35:41 -0000 On Mon, 21 Jan 2019 21:09:41 +0900 (JST) Yasuhiro KIMURA wrote: > Is it possible that I/O performance degrade while using ZFS for a long > time? And if answer is yes is there any way to recover performance > without making full backup and restore? How is the pool configured ? How full is it ? How well is the data striped (are some vdevs fuller than others) ? Are any of the drives showing trouble ? Do you run a regular scrub ? What does zpool status show ? I can think of several ways in which ZFS performance can become degraded (and there are probably a good many I haven't thought of) but time passing is not enough alone, something has to be going astray. Those questions should help pin down what. What it will take to recover depends greatly on the cause, you may find (for example) that replacing a flaky drive (not failing just making too many retries) will bring dramatic improvement or you might be unlucky and have developed hideously imbalanced stripes for which there is no cure but to wipe and rebuild. -- Steve O'Hara-Smith