From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <39D14B6C.4C9F6C26@us.oracle.com> Date: Tue, 26 Sep 2000 18:20:44 -0700 From: David Brower MIME-Version: 1.0 Subject: [linux-lvm] current lvm function questions Content-Transfer-Encoding: 7bit Sender: owner-linux-lvm Errors-To: owner-linux-lvm List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-lvm@msede.com Hi, sorry to ask what might be FAQs, but I couldn't find the answers on the list archive or the HOWTO. There may be overlap in my interests between lvm and md, so please straighten me out. Area 1: Stable device naming. Is there a way in Linux to get a stable name for a disk that survive reconfiguration and discovery randomization? One of the things linux has problems with is stable device naming. If you pull a disk out of a chain, the following devices will move up in the /dev entries, and not have the same name they had before. This can be a real problem with massive storage subsystems. I know of two ways of handling this. (1) is to slap a label on the disk, and make sure it shows up as the device in the label when the disk is discovered. (2) is to keep a separate database mapping devices to fixed locations. I think the label is the best idea. It seems to me that lvm already slaps a label on the disk when it does pvcreate. What i'm not sure of is whether the label used is (a) globally unique and suitable for stable device naming, or (b) tied to the device it happened to be on at the time the pvcreate was issued. Specifically, if a pv/vg/lv is created on /dev/sda6, and a subsequent reconfig has that partition show up as /dev/sdb3, does it still show up as /dev/lvname? 2. Raw device access Can lvm volumes be accessed as raw devices? If so, how? Is there /dev/rlvname? I'm sure /dev/fs falls in here somewhere... thanks! -dB