From nobody Wed Feb 16 04:19:53 2022 X-Original-To: freebsd-questions@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 2BEBE19B8CF6 for ; Wed, 16 Feb 2022 04:20:38 +0000 (UTC) (envelope-from parv.0zero9@gmail.com) Received: from mail-ua1-x92e.google.com (mail-ua1-x92e.google.com [IPv6:2607:f8b0:4864:20::92e]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Jz4WT0kC1z3LWH for ; Wed, 16 Feb 2022 04:20:37 +0000 (UTC) (envelope-from parv.0zero9@gmail.com) Received: by mail-ua1-x92e.google.com with SMTP id 10so507560uar.9 for ; Tue, 15 Feb 2022 20:20:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ziedGPKWqQ+tuAr+wj2idoxuo/1YIVmkAInqtUQEleI=; b=JxFb5tDazr2yyueYS+6VUmpu/QTwvfag/RqBhIFMAdhcF2vgLv3ssf9XES8dNwOY1p pDqSTmN8i2lyeliG/By+Qoms92R/XjNQJaT7RzlGbz3AOEeWysJG7NTxgPbN2kaKhB5o vmvwk8okRWTi5aSs4YOwfRSPrk/qymriS3eZ4CMt/ZNhRN/WC7j4Cz9PV32DJuxIcQxy LWrOb3+k7GYrSvVeCP1SZV9DZah16xBmNe4wOutWqs0z0l8NgJDFE7M2PW7XhU1JqHG5 3WQ3/OzsSpDxN1+9d5+FpQZ3EsviotTcin/mCC2Kyt00Wv6PkER0ZDkfqWDmdbrgRjm8 smzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ziedGPKWqQ+tuAr+wj2idoxuo/1YIVmkAInqtUQEleI=; b=1nXfkYr04gWdykfNK93KRR/nUj4iU6pT17mUPVv5C8k4eM747iekLYs6YpS/Ck4FwT k2aGIxCiqwAgrPjZlluJCyqOgFLK1NKuAJsFqHdO2c8jNJAJbLJvoCkRJO9WF8iWn6lb npBDfnnP/vo7JE33nSPK2OcbarURY3hUGMD4FQa3QVaU/N+mURpnkvs47kX5hDfY85aH ov7XUtT8gLBWvgaQ7wobwSsJVWD8u537tJg9bJy9yUqeQS/c65Kfp7Pka+5OSQPLfcIt qlXPpdE196DKejcbxbWHM3d3WHDgEauLOjDDirClBXtIv2/kUcReKXp7M2F4/iAwIZeW iuVQ== X-Gm-Message-State: AOAM531acZbFpplgHp0Cfm8NMjcADQSNByGYw+Y0sQIW32sPhfdZNbiR u6D7TBn78B6tXtG+nKxLQy4GPpuUgObbwWliXQ9rY/W9Spw= X-Google-Smtp-Source: ABdhPJydqy9cFujbSA7N5ZdQpg4659OOwru4kXYkNrsFc53kOlk5rOwQSj9lP1rHTnC2f/zac20mpANc5+UoQWJip+k= X-Received: by 2002:ab0:13a7:0:b0:33d:2d4:8b63 with SMTP id m36-20020ab013a7000000b0033d02d48b63mr315975uae.96.1644985236376; Tue, 15 Feb 2022 20:20:36 -0800 (PST) List-Id: User questions List-Archive: https://lists.freebsd.org/archives/freebsd-questions List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org MIME-Version: 1.0 References: In-Reply-To: From: "parv/freebsd" Date: Tue, 15 Feb 2022 18:19:53 -1000 Message-ID: Subject: Re: general zfs/zvol question To: Frank Leonhardt Cc: freebsd-questions@freebsd.org Content-Type: multipart/alternative; boundary="000000000000acce5305d81af83a" X-Rspamd-Queue-Id: 4Jz4WT0kC1z3LWH X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20210112 header.b=JxFb5tDa; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of parv0zero9@gmail.com designates 2607:f8b0:4864:20::92e as permitted sender) smtp.mailfrom=parv0zero9@gmail.com X-Spamd-Result: default: False [-4.00 / 15.00]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36:c]; FREEMAIL_FROM(0.00)[gmail.com]; MID_RHS_MATCH_FROMTLD(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; NEURAL_HAM_SHORT(-1.00)[-1.000]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; TAGGED_FROM(0.00)[freebsd]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20210112]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-questions@freebsd.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[2607:f8b0:4864:20::92e:from]; MLMMJ_DEST(0.00)[freebsd-questions]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] X-ThisMailContainsUnwantedMimeParts: N --000000000000acce5305d81af83a Content-Type: text/plain; charset="UTF-8" On Tue, Feb 15, 2022 at 1:25 AM Frank Leonhardt wrote: ... > The > main problem is the extreme fragmentation caused by copy-on-write. If > your data largely static (user files) it's not a big deal. If it's a > database, with millions of random access writes to the same file, that > file's going to be spread all over the zpool and there is nothing you > can do to stop it. I thought (someone else mentioned it) that fragmentation is not of contents of files but of available free space on a ZFS pool.? - parv > If you're using SSDs or 128Gb of cache you may not > notice the difference in access times, but by this stage you're not > comparing like for like. > > Operating systems like Windoze are always making small writes to disks > and IME end up fragmented in the same way a database would. > ... --000000000000acce5305d81af83a Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Tue, Feb 15, 2022 at 1:25 AM Frank Leonhardt wrote:<= /div>
...
<= /span>= The
main problem is the extreme fragmentation caused by copy-on-write. If
your data largely static (user files) it's not a big deal. If it's = a
database, with millions of random access writes to the same file, that
file's going to be spread all over the zpool and there is nothing you <= br> can do to stop it.

I thought (someone else mentioned it) = that fragmentation is not of contents
of files but of available free space on a ZFS = pool.?


- parv

=C2=A0
If you're using SSDs or 1= 28Gb of cache you may not
notice the difference in access times, but by this stage you're not comparing like for like.

Operating systems like Windoze are always making small writes to disks
and IME end up fragmented in the same way a database would.
...

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