From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xing Lin Subject: Re: When ceph synchronizes journal to disk? Date: Mon, 04 Mar 2013 21:47:05 -0700 Message-ID: <513578C9.4040602@cs.utah.edu> References: <513343D8.8050402@cs.utah.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-svr1.cs.utah.edu ([155.98.64.241]:58732 "EHLO mail-svr1.cs.utah.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932506Ab3CEErI (ORCPT ); Mon, 4 Mar 2013 23:47:08 -0500 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Gregory Farnum Cc: "ceph-devel@vger.kernel.org" Maybe it is easier to tell in this way. What we want to see is that the newly written data to stay in the=20 journal disk for as long as possible such that write workloads do not=20 compete for disk headers for read workloads. Any way to achieve that in= =20 Ceph? Thanks, Xing On 03/04/2013 09:55 AM, Gregory Farnum wrote: > The "journal [min|max] sync interval" values specify how frequently > the OSD's "FileStore" sends a sync to the disk. However, data is stil= l > written into the normal filesystem as it comes in, and the normal > filesystem continues to schedule normal dirty data writeouts. This is > good =97 it means that when we do send a sync down you don't need to > wait for all (30 seconds * 100MB/s) 3GB or whatever of data to go to > disk before it's completed. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html