From: Phillip Susi Subject: Re: [Bug 70121] New: Increasing efficiency of full data journaling Date: Wed, 05 Mar 2014 15:37:30 -0500 Message-ID: <53178B0A.9020906@ubuntu.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit To: bugzilla-daemon@bugzilla.kernel.org, linux-ext4@vger.kernel.org Return-path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120]:50607 "EHLO cdptpa-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755227AbaCEUhc (ORCPT ); Wed, 5 Mar 2014 15:37:32 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2/6/2014 5:38 AM, bugzilla-daemon@bugzilla.kernel.org wrote: > Full data journaling provides the ability that it is guaranteed > that a file will never be saved visible for the user in a damaged > state (except a hardware defect appears afterwards). But this has > the disadvantage that the writing througput is ~halfed as all files > are written 2 times. It does no such thing. To do that, a new kernel api is needed to allow the application to specify where transactions start/stop. Data journaling only makes sense for an external journal on an ssd or similar: then fsync() and friends can return as soon as the data hits the ssd and rely on it being safely migrated to the hdd in the future. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJTF4sKAAoJEI5FoCIzSKrwBpsH/35GAm2iqyNudw0JjJdceYqd PC+47MwQoJE2kcGLNCPVZLhRdHg+fWF6JKewnGAJXz6jsOIeblWyqyL03x8cCDMB 107ssZzXy8OllhczGp1oMR4q7bM0RiIwDjqD8qPJxYwTOHcoIp7RbyK0ER++LcE6 lISrSCyzyqpgo9o2oRAlAdP8/aioaOyiJbGpIhfH42Je+zG5k3mGwaCIuVvBR+Ef wm6rOqApxv6JwZy0s12alq6MUFMzE9qb9WTzLiDtPybSFzvUgt5brePi74HdJZHs JYjtUqk43q8wYCWcDcEjKb8q6/h/HGP296ZhM9CoXjq+HYqqWWXbl9T5F5+Nl6k= =nADc -----END PGP SIGNATURE-----