From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.gmx.net ([213.165.64.20]) by bombadil.infradead.org with smtp (Exim 4.68 #1 (Red Hat Linux)) id 1JXXHP-0002wr-9W for linux-mtd@lists.infradead.org; Fri, 07 Mar 2008 07:46:13 +0000 Subject: Re: Powerfail-tests and jffs2-sync-mount From: "Schlaegl Manfred jun." To: dedekind@infradead.org In-Reply-To: <1204870246.23706.53.camel@sauron> References: <1204821719.3426.33.camel@lisa.alm.archives.at> <1204870246.23706.53.camel@sauron> Content-Type: text/plain; charset=ISO-8859-1 Date: Fri, 07 Mar 2008 08:45:55 +0100 Message-Id: <1204875955.3476.13.camel@lisa.alm.archives.at> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi! Am Freitag, den 07.03.2008, 08:10 +0200 schrieb Artem Bityutskiy: > On Thu, 2008-03-06 at 17:41 +0100, Schlägl Manfred jun. wrote: > > Hi! > > > > I did some powerfail-testing of jffs2. > > > > Short overview (Contact me for details): > > Arch: ARM926EJ-S with 40MB rw jffs2 part on Samsung NAND-Flash > > Kernel: linux-2.6.12 (a little bit out of date, i know ;-)) > > Test: > > * Target-Loop > > * filesystem-consistency: > > * create dir > > * copy data(> eraseblock-size) to new file > > * delete a file > > * file-consistency: > > * logfile on jffs-part (simply appending text with echo) > > * External random-time reset: > > * external uC > > * generates reset every 120+rand(0..30) seconds > > * Run until no more space on filesystem > > Results: > > * test with sync-mounted jffs2 (mount -o sync): > > * duration 4:40 hours > > * 131 generated resets > > * consistent FS > > * consistent logfile > > * test with async mounted jffs2: > > * duration 4:10 hours > > * 118 generated resets > > * consistent FS > > * corrupted logfile (bad-chars, etc.) > > > > Now my question: Are there any non-obvious disadvantages, mounting jffs2 > > synchronal, except lower speed and a little(depends on usage) decreased > > flash-life-time (wear-out), or is this anyway the default approach? > > My understanding of the things is that this should not really matter. I > thought if you have some corruption in asynchronous mode, you should > have them in synchronous too, may its worth trying more synchronous mode > testing? > I thought it's a matter of file-buffers between the file-operations and jffs2, but these buffer should be flushed on close of the file, so there should be no problem with echo. I think i've to take a look on vfs, perhaps there is some buffering, or (even worst) some reodering of actions. Currently i've to do some other tests (bootloader bad-block-handling). After that I will work on some methodes to keep different files-types(config-files, log-files, ...) conistent in case of powerfail. So I will do some further tests on saturday or thursday. Best regards, Manfred Schlaegl