From owner-freebsd-fs@freebsd.org Tue Apr 5 02:26:23 2016 Return-Path: Delivered-To: freebsd-fs@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 2CAF3B03B81 for ; Tue, 5 Apr 2016 02:26:23 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-io0-x236.google.com (mail-io0-x236.google.com [IPv6:2607:f8b0:4001:c06::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id EA9A511D6 for ; Tue, 5 Apr 2016 02:26:22 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: by mail-io0-x236.google.com with SMTP id q128so3157788iof.3 for ; Mon, 04 Apr 2016 19:26:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc; bh=r2x2hE9odDMdTwGT/LxUxBVNKYeHEZZ5vw3q8i+sFf8=; b=veh6v2kU51XD+IXqOJ8Akn/gm/Lv99wmPCecfVM/OVcgZcOcsL+6nsczvzrTzqdzgt ahhtNrFzJP1V78quVHiCAnI6y+qIMq2ip+rTUrPVNO46GehqIFz49dnpoDE86hb2Y2nX xacvf4Vk4k+7wUcQh/2GugdeSdwU8rAee5Dpek3vWVVOINuGs5WN6SBd9aM326TlZs3P SI2gpJ795fra2/fgBU7CfAx7ag/EAS0w78D/wYgmjM9WWPghJ1BRFL5GH6Ymo9Kg74Qp VB3THnNxTsGZxn+QpF9ANzE90AelREP/9iaeLEMDU4pP0Jv9/FiEb3/D2e+xHEk7rhQH hp8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc; bh=r2x2hE9odDMdTwGT/LxUxBVNKYeHEZZ5vw3q8i+sFf8=; b=iJUSn4nWKjKcB+g/xIFpvetcBM/KgFEAz9uO5cAPkj0XSrXLcIn6689WL3/wNIi1AE 6QN8CLN9fA6dU/YOyHjRRxYbZiaLaaM9D5rnHUQPaKcjwNwu483lRdoodRnSA0ZbC6NL k3DxPC0RjcC4oEVXymYRGDfdbC3jNFBLK6wdpFRNGcukscR6QkCq+teVc52YrFzU1Ant Shy2HWS+H9pVmPxZqoR5CfNOAHq7gNxf8TJjdA7EH62XG3w5wVe90i84ARm0wJ+DxmJi Tsv1mxugYT/nfY74QMLkiuOtdUfBnGP0BuE3DWbG1d9WSutbOiC/7ShsRy7nelZbK9ik 2qkQ== X-Gm-Message-State: AD7BkJJoc4V6vrskoctYUbAOjM8blghY9mD9gfd3669Ya9z3S6xZVQqB1Tj78ChvxF3VwcLD+LvX11vWijFEmQ== MIME-Version: 1.0 X-Received: by 10.107.133.233 with SMTP id p102mr18977517ioi.1.1459823182345; Mon, 04 Apr 2016 19:26:22 -0700 (PDT) Received: by 10.107.161.6 with HTTP; Mon, 4 Apr 2016 19:26:22 -0700 (PDT) Received: by 10.107.161.6 with HTTP; Mon, 4 Apr 2016 19:26:22 -0700 (PDT) In-Reply-To: References: <34DB45E8-7E1F-4D7C-96FF-E0A403EE8000@omnigroup.com> <570311C5.4010702@quip.cz> Date: Mon, 4 Apr 2016 19:26:22 -0700 Message-ID: Subject: Re: ZFS pool with a large number of filesystems From: Freddie Cash To: Miroslav Lachman <000.fbsd@quip.cz> Cc: FreeBSD Filesystems , Wim Lewis Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Apr 2016 02:26:23 -0000 On Apr 4, 2016 6:16 PM, "Miroslav Lachman" <000.fbsd@quip.cz> wrote: > > Wim Lewis wrote on 04/05/2016 02:38: >> >> I'm curious how many ZFS filesystems are reasonable to have on a single machine (in a single zpool). We're contemplating a design in which we'd have tens of thousands, perhaps a couple hundred thousand, filesystems mounted out of the same pool. Before we go too far into investigating this idea: Does anyone have real-world experience doing something like that? Is it a situation that ZFS-on-FreeBSD is engineered to handle with good performance? Is there a rough estimate of the resources consumed per additional filesystem (in terms of kernel VM and disk space)? >> >> Thanks for any insight or advice (even, or especially, if the answer is "that's crazy, don't do that" :) ) > > > I donn't know about how many filesystems but I know that few hundereds of snapshots can make a noticeable slowdown for some zfs operations. > I think that basic "zfs list" will be painfully slow with tens of thousands of filesystems. > > Miroslav Lachman Adding "-o ,,etc" to limit what you query via "zfs list" really makes a difference. Especially on FreeBSD. PHK did a lot of work optimising that a release or two ago. "zfs list -o name -r -t all pool/fs" is many many many times faster than "zfs list -r -t all pool/fs" Cheers, Freddie Typos courtesy of my phone.