From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <20030311122715.2418.qmail@ispower.org> References: <1047381740.16925.116.camel@Zebra.vil.ite.mee.com> <20030311113153.GA839@tykepenguin.com> In-Reply-To: <20030311113153.GA839@tykepenguin.com> From: "Joao Rechena" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [linux-lvm] Re: How big are PEs by default? 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: Tue Mar 11 06:23:01 2003 List-Id: Content-Type: text/plain; format="flowed"; charset="us-ascii" To: linux-lvm@sistina.com Patrick Caulfield writes: > On Tue, Mar 11, 2003 at 11:22:20AM +0000, Paul Furness wrote: >> Hi. >> >> I'm trying to get LVM 1.0.7 going on our new production server. I've >> never used LVM before, but based on reccommendations and looking at what >> it can do, it looks like exactly what I need. >> >> For the reccord, it's a SMP Xeon system, running RedHat 7.3 plus current >> RH patches. >> >> I am confused about the defualt setting for Physical Extents when you >> run vgcreate on a new PV. >> >> Looking through the man page for vgcreate is says this: >> >> -s, --physicalextentsize PhysicalExtentSize[kKmMgGtT] >> Sets the physical extent size on physical volumes >> of this volume group. ................. The default >> of 32 MB allows LV sizes of ~2TB because as many as >> ~64k extents are supported per LV. >> >> A bit later, under "Examples." it says this: >> >> To create a volume group named test_vg using physical vol- >> umes /dev/hdk1, /dev/hdl1, and /dev/hdm1 with default >> physical extent size of 4MB: >> >> vgcreate test_vg /dev/sd[k-m]1 >> >> >> So what is the default? 4M or 32M? Or something else? Or should I simply >> forget about the default and pick a number? > > The default is 32MB, the example has not been updated. It used to be 4MB but > limiting LVs to 256MB by default soon became a problem for people. > > > >> Finally, is there any documentation that's more detailed than the HOWTO, >> and explains a bit more about the theory of LVM - what happens when you >> change the size of existing file systems, and so on? The HowTo is ok >> (although not all that great if you've never patched a kernel before), >> but necessarily brief. :) You could try to read the documentation of HP LVM, wich is a little more detailed, but be carefull, there are some commands that are diferent. I dont have the link here with me now but I can search later on. Regards rech -- Joao Rechena mailto:security@rechena.com http://www.rechena.com ================================ "Bow before me for I am root"