Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1na4Be-0003oA-DN for pgsql-admin@arkaria.postgresql.org; Thu, 31 Mar 2022 23:26:42 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1na4Bc-0000Mo-OU for pgsql-admin@arkaria.postgresql.org; Thu, 31 Mar 2022 23:26:40 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1na4Bc-0000Me-CL for pgsql-admin@lists.postgresql.org; Thu, 31 Mar 2022 23:26:40 +0000 Received: from mail-qk1-x729.google.com ([2607:f8b0:4864:20::729]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1na4BZ-0008UK-T2 for pgsql-admin@lists.postgresql.org; Thu, 31 Mar 2022 23:26:39 +0000 Received: by mail-qk1-x729.google.com with SMTP id v13so854785qkv.3 for ; Thu, 31 Mar 2022 16:26:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :references:from:in-reply-to; bh=ATZWjcVs/HQeKQkC7j/moF2QQmizbeir2t/FWkaCLuc=; b=IEkL6wGuICrUHvIW90kIn7TxNdays+uFWRMVvfyI/2SifeK/N94MaJHZ1NHNUFJfCw Dhy9U7Eg1yNl9A59cPaljZr+c4SFjPMie6DM+7Usn8qAP8g/Xw3occtw+pUtYTe/ldCh gZis5HkKqZKUxhdHogN4+kE7i+0vE+a1CTSXH5r2QR4qK5Sius09UUxC8qbJEYqx17Ah o6ln2r3DNwkM7iX+rtkWD4qrug0IU2feDZEAscfZjDNz3zK28qjsoieAA9xYepqRjq+m fe5v6hZdBMiiK7xFnIdpkLDn66ZrEG0zqQfFg45rVX0VuW4fskWqf59Wq48kJhM4YNSR aXpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:references:from:in-reply-to; bh=ATZWjcVs/HQeKQkC7j/moF2QQmizbeir2t/FWkaCLuc=; b=GaeNmef+tq3v2Bt3UE5QgR1A+j60Zz2DiXzSIYDKo2hcjJHdCfC9QTeGbReoomS+sR sz1hFIeFIOIdWLUdmNDlgPTz5Inc43wvwYl39mjok2eNl/PS0Sp4ep92YijNPvhkLJWi H4B0Nz2qq7ePSCJ23dP1DDm10Hlk0aO7C/CPqVMBZ7yUhORXBLcWm6tItaTTmdBaoEoD ss6760k6rDbXwXOZn5RrxZqHBWSGM2zut5UICkqHZNRCsm3/2x8+gByKV6RzL/Rz052s 9NscLvzY9hV5z/RZTVa9BF40nWhqcCz2hwUZtGJPa3L1kymVCZ09I3XC3rfZeTxXHbAT znaw== X-Gm-Message-State: AOAM532TXL7BXv88VzLmyTb9vD3Evp+mCaazJIE8jKzhFgbyo2Vz1zG7 i+97qYjBG4vflmlhWgwXv5LaJYeNUgpbLQ== X-Google-Smtp-Source: ABdhPJw5DyAZ+SvWveJnsyJZ36r+rP/HkjeAtXLvGABgLp5PainhlyWV9cSFO8afsbgC6q4G+36WhA== X-Received: by 2002:a37:bac6:0:b0:663:5fde:226f with SMTP id k189-20020a37bac6000000b006635fde226fmr5244923qkf.137.1648769196461; Thu, 31 Mar 2022 16:26:36 -0700 (PDT) Received: from [192.168.2.100] (pool-72-79-19-93.nwrknj.east.verizon.net. [72.79.19.93]) by smtp.gmail.com with ESMTPSA id v7-20020ac85787000000b002e1c8376517sm517934qta.22.2022.03.31.16.26.36 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 31 Mar 2022 16:26:36 -0700 (PDT) Content-Type: multipart/alternative; boundary="------------W4k5OlEu2R70DHFGzdRQMnXT" Message-ID: <4fe1d719-4f08-7b10-90c3-43514453757d@gmail.com> Date: Thu, 31 Mar 2022 19:26:35 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: WAL & ZFS Content-Language: en-US To: pgsql-admin@lists.postgresql.org References: From: Mladen Gogala In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk This is a multi-part message in MIME format. --------------W4k5OlEu2R70DHFGzdRQMnXT Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 3/30/22 17:32, Scott Ribe wrote: > I've read all the info I could find re running PG on ZFS: turn off full page writes, turn on lz4, tweak recordsize so as to take advantage of compression, etc. One thing I haven't seen is whether a separate volume for WAL would benefit from a larger recordsize. Or any other tweaks??? > > -- > Scott Ribe > scott_ribe@elevated-dev.com > https://www.linkedin.com/in/scottribe/ > > > > > Phoronix has tested ZFS against Ext3, Ext4 and XFS. ZFS was consistently performing worse than all other file systems. Here is the test with Oracle: https://blog.docbert.org/oracle-on-zfs/ Here are several articles that caution against ZFS: https://forums.servethehome.com/index.php?threads/very-slow-zfs-raidz2-performance-on-truenas-12.33094/ https://serverfault.com/questions/791154/zfs-good-read-but-poor-write-speeds https://www.phoronix.com/scan.php?page=article&item=ubuntu1910-ext4-zfs&num=3 And finally, this: https://storytime.ivysaur.me/posts/why-not-zfs/ I would consider Linux ZFS only for toy databases that do not hold any serious data. -- Mladen Gogala Database Consultant Tel: (347) 321-1217 https://dbwhisperer.wordpress.com --------------W4k5OlEu2R70DHFGzdRQMnXT Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit
On 3/30/22 17:32, Scott Ribe wrote:
I've read all the info I could find re running PG on ZFS: turn off full page writes, turn on lz4, tweak recordsize so as to take advantage of compression, etc. One thing I haven't seen is whether a separate volume for WAL would benefit from a larger recordsize. Or any other tweaks???

--
Scott Ribe
scott_ribe@elevated-dev.com
https://www.linkedin.com/in/scottribe/

Phoronix has tested ZFS against Ext3, Ext4 and XFS. ZFS was consistently performing worse than all other file systems. Here is the test with Oracle:

https://blog.docbert.org/oracle-on-zfs/

Here are several articles that caution against ZFS:

https://forums.servethehome.com/index.php?threads/very-slow-zfs-raidz2-performance-on-truenas-12.33094/

https://serverfault.com/questions/791154/zfs-good-read-but-poor-write-speeds

https://www.phoronix.com/scan.php?page=article&item=ubuntu1910-ext4-zfs&num=3

And finally, this: https://storytime.ivysaur.me/posts/why-not-zfs/

I would consider Linux ZFS only for toy databases that do not hold any serious data.


-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com
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