From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 28 Feb 2001 12:34:07 +0000 From: "Heinz J. Mauelshagen" Subject: Re: [linux-lvm] Possible to raise Max LV? Message-ID: <20010228123407.G4361@srv.sistina.com> References: <20010227213517.G29642@vestdata.no> <200102272055.f1RKt5S27720@webber.adilger.net> <20010227150417.A22325@omnifarious.mn.org> Mime-Version: 1.0 In-Reply-To: <20010227150417.A22325@omnifarious.mn.org>; from hopper@omnifarious.mn.org on Tue, Feb 27, 2001 at 03:04:17PM -0600 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: List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-lvm@sistina.com On Tue, Feb 27, 2001 at 03:04:17PM -0600, Eric M. Hopper wrote: > On Tue, Feb 27, 2001 at 01:55:05PM -0700, Andreas Dilger wrote: > > Ragnar Kj_rstad writes: > > > What about increesing the [PE size] default, to say 32 MB? > > > 32 MB should be enough for everyone (because of the 2TB limit), and 16 > > > MB waste on every PV isn't that bad. > > > > So says the guy from a company called "Big Storage" ;-). However, > > I've seen several people who make multiple partitions on a single > > disk, and then turn these into PVs (don't ask me why), so they would > > be wasting 16MB per partition. Most people will not need 2TB LVs for > > some time to come. However, if your systems usually have large LVs, > > then it is OK for you to increase the default for your systems. > > I actually intend to for mine sometime later because it reduces > the fragmentation problem. I know it shouldn't be that big a deal with > 4M PEs, but with 32M PEs it'll be even less of a deal. :-) > > I actually thinking of generally scaling my PEs to around 0.1% > of my total available space on the theory that allocation of finer > grained chunks than that is kinda silly. > > If I weren't working on some stuff of my own, I'd dive in and > see if I could write a defrag utility for LVM. The part I'm not sure > how I'd handle would be striped LVs. > > Have fun (if at all possible), > -- As Andreas already pointed out: 4M basically is a good value to keep the overhead small. As I stated in another email: the ~64k extents per LV limit will likely disappear in the future (no date though ;-). For now you *need* to plan for the maximum LV size you want to create/extend to during planning of the VG(s). 2T is the Linux limit per block device anyway at least until Linux 2.5 changes that. -- Regards, Heinz -- The LVM Guy -- *** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them *** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Sistina Software Inc. Senior Consultant/Developer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@Sistina.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-