From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from nm12-vm0.bullet.mail.ne1.yahoo.com ([98.138.91.51]) by merlin.infradead.org with smtp (Exim 4.76 #1 (Red Hat Linux)) id 1Sbthe-0004ZM-Nx for linux-mtd@lists.infradead.org; Tue, 05 Jun 2012 13:21:43 +0000 Message-ID: <1338902500.33577.YahooMailNeo@web39302.mail.mud.yahoo.com> Date: Tue, 5 Jun 2012 06:21:40 -0700 (PDT) From: Doug Kehn Subject: UBI: Single versus Multiple Images To: "linux-mtd@lists.infradead.org" MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Reply-To: Doug Kehn List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Everyone,=0A=0AI have the following NAND flash MTD layout (presently JFF= S2):=0A=0A* Boot-loader=0A* Kernel=0A* Root file-system (rootfs)=0A=0A* Dat= a=0A=0AI'm going to switch from JFFS2 to UBI/UBIFS.=A0 I'm wondering if it = is better to create a single UBI image containing both rootfs and data volu= mes or to create separate UBI images (each with a single volume) or is the = answer it depends?=0A=0AThe data volume will be used for logging data.=A0 T= he volume won't completely fill as old data will be purged to make room for= new data.=A0 For the single image multiple volume case, if I understand th= e =0Adocumentation correctly, UBI will use all PEB from both volumes for ma= pping per-volume LEB, =0Acorrect?=A0 If my understanding is correct, then i= t's possible, after enough time, maximum PEB erase count will be reached an= d both rootfs and data volumes will be read-only?=A0 If the goal is to keep= the rootfs volume writable, even if the data volume become read-only, then= would it be better to create multiple UBI images?=A0 Or is my understandin= g all wrong?=0A=0AThanks,=0A...doug