From owner-freebsd-fs@freebsd.org Tue Apr 5 01:15:53 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 27B79B023D7 for ; Tue, 5 Apr 2016 01:15:53 +0000 (UTC) (envelope-from 000.fbsd@quip.cz) Received: from elsa.codelab.cz (elsa.codelab.cz [94.124.105.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E24CC11FF for ; Tue, 5 Apr 2016 01:15:52 +0000 (UTC) (envelope-from 000.fbsd@quip.cz) Received: from elsa.codelab.cz (localhost [127.0.0.1]) by elsa.codelab.cz (Postfix) with ESMTP id 055562845A; Tue, 5 Apr 2016 03:15:51 +0200 (CEST) Received: from illbsd.quip.test (ip-86-49-16-209.net.upcbroadband.cz [86.49.16.209]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by elsa.codelab.cz (Postfix) with ESMTPSA id 21B6628417; Tue, 5 Apr 2016 03:15:50 +0200 (CEST) Message-ID: <570311C5.4010702@quip.cz> Date: Tue, 05 Apr 2016 03:15:49 +0200 From: Miroslav Lachman <000.fbsd@quip.cz> User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:35.0) Gecko/20100101 Firefox/35.0 SeaMonkey/2.32 MIME-Version: 1.0 To: Wim Lewis , "freebsd-fs@FreeBSD.org" Subject: Re: ZFS pool with a large number of filesystems References: <34DB45E8-7E1F-4D7C-96FF-E0A403EE8000@omnigroup.com> In-Reply-To: <34DB45E8-7E1F-4D7C-96FF-E0A403EE8000@omnigroup.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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 01:15:53 -0000 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