From owner-freebsd-fs@FreeBSD.ORG Sun Nov 17 15:27:05 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 08D03956 for ; Sun, 17 Nov 2013 15:27:05 +0000 (UTC) Received: from frv197.fwdcdn.com (frv197.fwdcdn.com [212.42.77.197]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id B92A42330 for ; Sun, 17 Nov 2013 15:27:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=ukr.net; s=ffe; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To:Message-Id:To:Subject:From:Date; bh=Dguf9f2/weyIuwsabfpQGAzHnAAlHqcpnCnHyuXJ3YI=; b=Dsrc/U7yMjkRI0K3g6LHFCXmOTd88j/IF52DajIx7OcBfbNEcsBUkkXyIvgLj073JHPW57iGUumCwNO/IKeeNcEPErQ5Alm1g/rECK9mfJpej9a4T8tduwdvon8McauHZd419lZrEFRhCapJLrHZm3oDZfrcHcEiRn+C9Gdfpw4=; Received: from [10.10.10.45] (helo=frv45.ukr.net) by frv197.fwdcdn.com with smtp ID 1Vi4FX-000Mxh-Hd for freebsd-fs@freebsd.org; Sun, 17 Nov 2013 17:26:59 +0200 Date: Sun, 17 Nov 2013 17:26:58 +0200 From: Vladimir Sharun Subject: Re: ZFS: Memory needed for managing L2ARC To: freebsd-fs@freebsd.org X-Mailer: mail.ukr.net 5.0 Message-Id: <1384701881.854989070.jd2fimne@frv45.ukr.net> In-Reply-To: References: MIME-Version: 1.0 Received: from atz@ukr.net by frv45.ukr.net; Sun, 17 Nov 2013 17:26:59 +0200 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: binary Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.16 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 17 Nov 2013 15:27:05 -0000 Depending on average block size cached. In my experience it varies from 0,3% to 5%. If you store lot of small files, consider 5-6%, mostly large files - 0,5%. Dear colleagues, are there any "real" estimations on how much memory is needed for having efficient, say, 1T of L2ARC? stable/amd64, of course. I have backup storage server, where pool size is targeted to a few hundreds of terabytes (currently ~35T), and hot set is usually less than 512G-1T. quick googling leads to some Solaris/Illumos documents, but even them are not bright enough in answer that. Thanks! -- Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] [ FreeBSD committer: marck@FreeBSD.org ] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------ _______________________________________________ freebsd-fs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-fs To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" From owner-freebsd-fs@FreeBSD.ORG Sun Nov 17 15:28:41 2013 Return-Path: Delivered-To: freebsd-fs@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id CEFB19DA for ; Sun, 17 Nov 2013 15:28:41 +0000 (UTC) Received: from elsa.codelab.cz (elsa.codelab.cz [94.124.105.4]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 90741233D for ; Sun, 17 Nov 2013 15:28:41 +0000 (UTC) Received: from elsa.codelab.cz (localhost [127.0.0.1]) by elsa.codelab.cz (Postfix) with ESMTP id 7FC722842E; Sun, 17 Nov 2013 16:28:33 +0100 (CET) Received: from [192.168.1.2] (ip-89-177-49-222.net.upcbroadband.cz [89.177.49.222]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by elsa.codelab.cz (Postfix) with ESMTPSA id 00CD32842B; Sun, 17 Nov 2013 16:28:30 +0100 (CET) Message-ID: <5288E09E.4010707@quip.cz> Date: Sun, 17 Nov 2013 16:28:30 +0100 From: Miroslav Lachman <000.fbsd@quip.cz> User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9.1.19) Gecko/20110420 Lightning/1.0b1 SeaMonkey/2.0.14 MIME-Version: 1.0 To: Dmitry Morozovsky Subject: Re: ZFS: Memory needed for managing L2ARC References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@FreeBSD.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 17 Nov 2013 15:28:41 -0000 Dmitry Morozovsky wrote: > Dear colleagues, > > are there any "real" estimations on how much memory is needed for having > efficient, say, 1T of L2ARC? stable/amd64, of course. > > I have backup storage server, where pool size is targeted to a few hundreds of > terabytes (currently ~35T), and hot set is usually less than 512G-1T. > > quick googling leads to some Solaris/Illumos documents, but even them are not > bright enough in answer that. I have some old informations in a bookmarks: Re: [zfs-discuss] ZFS ZIL + L2ARC SSD Setup http://www.mail-archive.com/zfs-discuss@opensolaris.org/msg34674.html Approximately 200 bytes per record. I use the following example: Suppose we use a Seagate LP 2 TByte disk for the L2ARC + Disk has 3,907,029,168 512 byte sectors, guaranteed + Workload uses 8 kByte fixed record size RAM needed for arc_buf_hdr entries + Need = ~(3,907,029,168 - 9,232) * 200 / 16 = ~48 GBytes http://www.mail-archive.com/zfs-discuss@opensolaris.org/msg34677.html I hope this helps Miroslav Lachman