From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0B60C432C0 for ; Mon, 2 Dec 2019 10:49:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81128214AF for ; Mon, 2 Dec 2019 10:49:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="IUguLsxf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727381AbfLBKtb (ORCPT ); Mon, 2 Dec 2019 05:49:31 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:52174 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726276AbfLBKtb (ORCPT ); Mon, 2 Dec 2019 05:49:31 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xB2AnP5A077795; Mon, 2 Dec 2019 10:49:25 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2019-08-05; bh=isbovAW+bWhvVDQxtDyXRidikyBLx/E05PkjOJ4gR7o=; b=IUguLsxf96M32U2KEJfPOUYc126g8+bSX1pn+Es12W3/0cnjGIz6QRIODFGWMqWP9C5y D31juIetOFU34PdRnlFfaA2GZlmBZf+FBNe+NR992nZxbmbUUw7uPUOjJoD+aL/bw0Em DAMA5lmdNG26x+2LlvPn0QYT8qjpsF3Uq0pP7Ajx17qdtzMsCRAwjG+1v8pvpflMNIcq 3osQnP0ptENKuVOME3kP1PD3oUJKiZiCk9atRWYWhhDvIU9dMgcTyIHHkCAK8J+m6M93 LKFeoOUtrzQj1proRSmibj6I4k/UECILc43WGYqaSd+PBg2tm+GhdBj4oWGsPGC7fNLu kQ== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 2wkgcpy48m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 02 Dec 2019 10:49:25 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xB2AnKjv098387; Mon, 2 Dec 2019 10:49:24 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 2wm2jm780c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 02 Dec 2019 10:49:20 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xB2AmFqU012800; Mon, 2 Dec 2019 10:48:15 GMT Received: from [192.168.1.119] (/39.109.145.141) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 02 Dec 2019 02:48:15 -0800 Subject: Re: BTRFS subvolume RAID level To: waxhead@dirtcellar.net, Btrfs BTRFS References: <494b0df1-2aab-5169-836d-e381498f64db@dirtcellar.net> From: Anand Jain Message-ID: Date: Mon, 2 Dec 2019 18:48:07 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <494b0df1-2aab-5169-836d-e381498f64db@dirtcellar.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9458 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=887 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912020099 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9458 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=951 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912020099 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org > I imagine that RAIDc4 for example could potentially give a grotesque > speed increase for parallel read operations once BTRFS learns to > distribute reads to the device with the least waitqueue / fastest devices. That exactly was the objective of the Readmirror patch in the ML. It proposed a framework to change the readmirror policy as needed. Thanks, Anand