From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3DC8DE98.FBFF5B8@silicide.dk> From: Jon Bendtsen MIME-Version: 1.0 Subject: Re: [linux-lvm] LV Fragmentation determination References: Content-Transfer-Encoding: 7bit Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: Date: Wed Nov 6 03:20:01 2002 List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-lvm@sistina.com Donald Thompson wrote: > > First off, can LV's become fragmented across a PV/VG? If yes then... yes they can. But that depends on how you made it. The default is to use the next free PE, but you can specify the PE's. > I'm looking for an easy way to determine how fragmented an LV might been > inside the VG. Is there any command I can run that'll give me nice > estimate on this? i dont know, but cant you use lvdisplay, pvdisplay, or the other display commands to see the PE numbers ? > Assuming theres no such command, can I determine this by looking at the > PE's displayed from an 'lvdisplay -v' command? I'm guessing it'd be pretty > easy to write a script that analyzes the PE numbers and looks for skips in > the sequence to give myself an idea of the amount of fragmention for the > LV. Or am I competely wrong thinking you can use PE's to make such a > determination? i think you can > I do shrinks and enlarges for different LV's sometimes on an almost daily > basis, and my VG's are getting to be very old. So I'm curious to see how > fragmentated my LVs have become. Properly much, but is that bad ? I mean, sure you have to move the head every PE size, but how big are your PE size ? The default is 4MB. JonB