From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4E3670C0.1070503@redhat.com> Date: Mon, 01 Aug 2011 10:24:16 +0100 From: "Bryn M. Reeves" MIME-Version: 1.0 References: <883D98939E388E429EE8D771168A6560027ED144AF@USCMIMAIL1.corp.amdocs.com> In-Reply-To: <883D98939E388E429EE8D771168A6560027ED144AF@USCMIMAIL1.corp.amdocs.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [linux-lvm] Question, what is the first 384 cyclinder in the PV? Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="windows-1252" To: LVM general discussion and development Cc: Jewsco Pius Jacquez On 07/29/2011 06:35 PM, Jewsco Pius Jacquez wrote: > I=E2=80=99m sorry, I mean the first 384 sector. It's space reserved for lvm2 data used to manage the volume; This part of t= he device contains the LVM2 label and metadata area. (it's before the first physical extent in the volume). > I am using RHEL5.6 kernel 2.6.18-238.12.1.el5 and have lvm2-2.02.74-5.el5= . Here=20 > is my lvm.conf. >=20 > Can an application data exist here? Like oracle data.. Not generally but lvm2 does not necessarily write to every location in this region when initialising a new device so if there was existing data on the device when pvcreate/vgcreate ran it will not have been overwritten. > For instance, if I dd out from a PV with bs=3D512 and count=3D384 and I s= aw oracle=20 > data on it, is this ok? It's not possible to say with this information - has oracle been configured= to use the whole disk? If so then that's an error but if the data you are seeing is just "stale" d= ata from a previous use of the device it's not going to cause any problems. Regards, Bryn.