From owner-freebsd-fs@freebsd.org Sun Apr 12 11:26:25 2020 Return-Path: Delivered-To: freebsd-fs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 836882BAA8E for ; Sun, 12 Apr 2020 11:26:25 +0000 (UTC) (envelope-from agapon@gmail.com) Received: from mail-lj1-f169.google.com (mail-lj1-f169.google.com [209.85.208.169]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 490TwJ30hyz410n for ; Sun, 12 Apr 2020 11:26:24 +0000 (UTC) (envelope-from agapon@gmail.com) Received: by mail-lj1-f169.google.com with SMTP id m8so6158650lji.1 for ; Sun, 12 Apr 2020 04:26:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=LHjBG1R8im3w7L4yD/xOjxbruHa32JHNSxqhJevk/Js=; b=cj+jpsGc0ndf5zhwMW3BUB+E7nsGJn3Cf5wLerZXt+n4WKSuIJsGm05lWXoHLagwCt RmubE2CR4wuKNaW6Xx2SogyX9sevYeaP1bDPuMiRBOaVfW5ar654bXAszLcgJPxeHhrV jhEKmo3BDIupl54C1w8Su4Bdw3Ktgtz8Mx7QSfi1LpMUcsCL5R2rqAF0o7wDTjOZMmoZ pRY44u1FG6nRq6c9KU7MrG1bMobCHso1i0yKgoRdvdLEIIMhG/XmeIkpvEHNxpZ35zQM iMVVNB1qTtV8P+IRo69N2blhUMIxmrbe4cQgj4oumtz3nAPPF1ikMftmo7aP6RtF3JsG Oilw== X-Gm-Message-State: AGi0PubNULtSjWXnoKX9kyMnesDmSgLXMaUDlSVQeed8/VGahdYbURTI Kd18XO6egyeV8riYu0JZSJYZJc5HH6Q= X-Google-Smtp-Source: APiQypLecpK3WaL+evIoWvpYqowQPMUmWwvYvwpE+qvKsnsoqymnOC7UmiuBJHA8Bzu326jWknOVaA== X-Received: by 2002:a2e:a362:: with SMTP id i2mr7845052ljn.52.1586690781986; Sun, 12 Apr 2020 04:26:21 -0700 (PDT) Received: from [192.168.0.88] (east.meadow.volia.net. [93.72.151.96]) by smtp.googlemail.com with ESMTPSA id p23sm5755187lfc.95.2020.04.12.04.26.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 12 Apr 2020 04:26:21 -0700 (PDT) Subject: Re: ZFS server has gone crazy slow To: Peter Eriksson , freebsd-fs References: <2182C27C-A5D3-41BF-9CE9-7C6883E43074@distal.com> <20200411174831.GA54397@fuz.su> <6190573D-BCA7-44F9-86BD-0DCBB1F69D1D@distal.com> <6fd7a561-462e-242d-5057-51c52d716d68@wp.pl> <7AA1EA07-6041-464A-A39A-158ACD1DC11C@distal.com> From: Andriy Gapon Openpgp: preference=signencrypt Autocrypt: addr=avg@FreeBSD.org; prefer-encrypt=mutual; keydata= mQINBFm4LIgBEADNB/3lT7f15UKeQ52xCFQx/GqHkSxEdVyLFZTmY3KyNPQGBtyvVyBfprJ7 mAeXZWfhat6cKNRAGZcL5EmewdQuUfQfBdYmKjbw3a9GFDsDNuhDA2QwFt8BmkiVMRYyvI7l N0eVzszWCUgdc3qqM6qqcgBaqsVmJluwpvwp4ZBXmch5BgDDDb1MPO8AZ2QZfIQmplkj8Y6Z AiNMknkmgaekIINSJX8IzRzKD5WwMsin70psE8dpL/iBsA2cpJGzWMObVTtCxeDKlBCNqM1i gTXta1ukdUT7JgLEFZk9ceYQQMJJtUwzWu1UHfZn0Fs29HTqawfWPSZVbulbrnu5q55R4PlQ /xURkWQUTyDpqUvb4JK371zhepXiXDwrrpnyyZABm3SFLkk2bHlheeKU6Yql4pcmSVym1AS4 dV8y0oHAfdlSCF6tpOPf2+K9nW1CFA8b/tw4oJBTtfZ1kxXOMdyZU5fiG7xb1qDgpQKgHUX8 7Rd2T1UVLVeuhYlXNw2F+a2ucY+cMoqz3LtpksUiBppJhw099gEXehcN2JbUZ2TueJdt1FdS ztnZmsHUXLxrRBtGwqnFL7GSd6snpGIKuuL305iaOGODbb9c7ne1JqBbkw1wh8ci6vvwGlzx rexzimRaBzJxlkjNfMx8WpCvYebGMydNoeEtkWldtjTNVsUAtQARAQABtB5BbmRyaXkgR2Fw b24gPGF2Z0BGcmVlQlNELm9yZz6JAlQEEwEIAD4WIQS+LEO7ngQnXA4Bjr538m7TUc1yjwUC WbgsiAIbIwUJBaOagAULCQgHAgYVCAkKCwIEFgIDAQIeAQIXgAAKCRB38m7TUc1yj+JAEACV l9AK/nOWAt/9cufV2fRj0hdOqB1aCshtSrwHk/exXsDa4/FkmegxXQGY+3GWX3deIyesbVRL rYdtdK0dqJyT1SBqXK1h3/at9rxr9GQA6KWOxTjUFURsU7ok/6SIlm8uLRPNKO+yq0GDjgaO LzN+xykuBA0FlhQAXJnpZLcVfPJdWv7sSHGedL5ln8P8rxR+XnmsA5TUaaPcbhTB+mG+iKFj GghASDSfGqLWFPBlX/fpXikBDZ1gvOr8nyMY9nXhgfXpq3B6QCRYKPy58ChrZ5weeJZ29b7/ QdEO8NFNWHjSD9meiLdWQaqo9Y7uUxN3wySc/YUZxtS0bhAd8zJdNPsJYG8sXgKjeBQMVGuT eCAJFEYJqbwWvIXMfVWop4+O4xB+z2YE3jAbG/9tB/GSnQdVSj3G8MS80iLS58frnt+RSEw/ psahrfh0dh6SFHttE049xYiC+cM8J27Aaf0i9RflyITq57NuJm+AHJoU9SQUkIF0nc6lfA+o JRiyRlHZHKoRQkIg4aiKaZSWjQYRl5Txl0IZUP1dSWMX4s3XTMurC/pnja45dge/4ESOtJ9R 8XuIWg45Oq6MeIWdjKddGhRj3OohsltKgkEU3eLKYtB6qRTQypHHUawCXz88uYt5e3w4V16H lCpSTZV/EVHnNe45FVBlvK7k7HFfDDkryLkCDQRZuCyIARAAlq0slcsVboY/+IUJdcbEiJRW be9HKVz4SUchq0z9MZPX/0dcnvz/gkyYA+OuM78dNS7Mbby5dTvOqfpLJfCuhaNYOhlE0wY+ 1T6Tf1f4c/uA3U/YiadukQ3+6TJuYGAdRZD5EqYFIkreARTVWg87N9g0fT9BEqLw9lJtEGDY EWUE7L++B8o4uu3LQFEYxcrb4K/WKmgtmFcm77s0IKDrfcX4doV92QTIpLiRxcOmCC/OCYuO jB1oaaqXQzZrCutXRK0L5XN1Y1PYjIrEzHMIXmCDlLYnpFkK+itlXwlE2ZQxkfMruCWdQXye syl2fynAe8hvp7Mms9qU2r2K9EcJiR5N1t1C2/kTKNUhcRv7Yd/vwusK7BqJbhlng5ZgRx0m WxdntU/JLEntz3QBsBsWM9Y9wf2V4tLv6/DuDBta781RsCB/UrU2zNuOEkSixlUiHxw1dccI 6CVlaWkkJBxmHX22GdDFrcjvwMNIbbyfQLuBq6IOh8nvu9vuItup7qemDG3Ms6TVwA7BD3j+ 3fGprtyW8Fd/RR2bW2+LWkMrqHffAr6Y6V3h5kd2G9Q8ZWpEJk+LG6Mk3fhZhmCnHhDu6CwN MeUvxXDVO+fqc3JjFm5OxhmfVeJKrbCEUJyM8ESWLoNHLqjywdZga4Q7P12g8DUQ1mRxYg/L HgZY3zfKOqcAEQEAAYkCPAQYAQgAJhYhBL4sQ7ueBCdcDgGOvnfybtNRzXKPBQJZuCyIAhsM BQkFo5qAAAoJEHfybtNRzXKPBVwQAKfFy9P7N3OsLDMB56A4Kf+ZT+d5cIx0Yiaf4n6w7m3i ImHHHk9FIetI4Xe54a2IXh4Bq5UkAGY0667eIs+Z1Ea6I2i27Sdo7DxGwq09Qnm/Y65ADvXs 3aBvokCcm7FsM1wky395m8xUos1681oV5oxgqeRI8/76qy0hD9WR65UW+HQgZRIcIjSel9vR XDaD2HLGPTTGr7u4v00UeTMs6qvPsa2PJagogrKY8RXdFtXvweQFz78NbXhluwix2Tb9ETPk LIpDrtzV73CaE2aqBG/KrboXT2C67BgFtnk7T7Y7iKq4/XvEdDWscz2wws91BOXuMMd4c/c4 OmGW9m3RBLufFrOag1q5yUS9QbFfyqL6dftJP3Zq/xe+mr7sbWbhPVCQFrH3r26mpmy841ym dwQnNcsbIGiBASBSKksOvIDYKa2Wy8htPmWFTEOPRpFXdGQ27awcjjnB42nngyCK5ukZDHi6 w0qK5DNQQCkiweevCIC6wc3p67jl1EMFY5+z+zdTPb3h7LeVnGqW0qBQl99vVFgzLxchKcl0 R/paSFgwqXCZhAKMuUHncJuynDOP7z5LirUeFI8qsBAJi1rXpQoLJTVcW72swZ42IdPiboqx NbTMiNOiE36GqMcTPfKylCbF45JNX4nF9ElM0E+Y8gi4cizJYBRr2FBJgay0b9Cp Message-ID: <575c01de-b503-f4f9-2f13-f57f428f53ec@FreeBSD.org> Date: Sun, 12 Apr 2020 14:26:20 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:60.0) Gecko/20100101 Firefox/60.0 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 490TwJ30hyz410n X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of agapon@gmail.com designates 209.85.208.169 as permitted sender) smtp.mailfrom=agapon@gmail.com X-Spamd-Result: default: False [-2.25 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:209.85.128.0/17:c]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-fs@freebsd.org]; DMARC_NA(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-1.00)[-0.998,0]; RCVD_COUNT_THREE(0.00)[3]; MIME_TRACE(0.00)[0:+]; TO_DN_ALL(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; RCVD_IN_DNSWL_NONE(0.00)[169.208.85.209.list.dnswl.org : 127.0.5.0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; IP_SCORE(-0.25)[ip: (-0.39), ipnet: 209.85.128.0/17(-0.40), asn: 15169(-0.43), country: US(-0.05)]; FORGED_SENDER(0.30)[avg@FreeBSD.org,agapon@gmail.com]; RWL_MAILSPIKE_POSSIBLE(0.00)[169.208.85.209.rep.mailspike.net : 127.0.0.17]; R_DKIM_NA(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US]; FROM_NEQ_ENVFROM(0.00)[avg@FreeBSD.org,agapon@gmail.com]; MID_RHS_MATCH_FROM(0.00)[]; RECEIVED_SPAMHAUS_PBL(0.00)[96.151.72.93.khpj7ygk5idzvmvt5x4ziurxhy.zen.dq.spamhaus.net : 127.0.0.10] X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Apr 2020 11:26:25 -0000 On 12/04/2020 00:24, Peter Eriksson wrote: > Another fun thing that might happen is if you reboot your server and happen > to have a lot of queued up writes in the ZIL (for example if you did a “zfs > destroy -d -r POOL@snapshots” (deferred(background) destroys of snapshots) > and do a hard reboot while it’s busy it will “write out” those queued > transactions at filesystem mount time during the boot sequence Just nitpicking on two bits of incorrect information here. First, zfs destroy never uses ZIL. Never. ZIL is used only for ZPL operations like file writes, renames, removes, etc. The things that you can do with Posix system calls (~ VFS KPI). Second, zfs destroy -d is not a background destroy. It is a deferred destroy. That means that either the destroy is done immediately if a snapshot has no holds which means no user holds and no clones. Or the destroy is postponed until holds are gone, that is, the last clone or the last user hold is removed. Note, however, that unless you have a very ancient pool version destroying a snapshot means that the snapshot object is removed and all blocks belonging to the snapshot are queued for freeing. Their actual freeing is done asynchronously ("in background") and can be spread over multiple TXG periods. That's done regardless of whether -d was used. -- Andriy Gapon