From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: mdadm does not create partition devices whatsoever, "partitionable" functionality broken Date: Sat, 14 May 2011 16:24:27 +0600 Message-ID: <20110514162427.143668d6@natsu> References: <4DCD4A83.8060202@pulseforce.com> <4DCD6119.3080705@turmel.org> <4DCD67EF.1070602@pulseforce.com> <4DCD6B27.70402@pulseforce.com> <20110513234055.4307c536@natsu> <4DCD72AF.1070809@pulseforce.com> <4DCD75FE.8010703@turmel.org> <4DCD7E78.6050000@pulseforce.com> <4DCD84E1.3040704@turmel.org> <20110514013221.552dc8ef@natsu> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/VGffokO2aS/A6mEhw5mrkP6"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: David Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/VGffokO2aS/A6mEhw5mrkP6 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sat, 14 May 2011 12:10:56 +0200 David Brown wrote: > What is perhaps more relevant, is can filesystems see the fragmentation=20 > of the LV's? I don't know the answer. No, of course they can't. > Still, you don't usually have many segments in an LV - if you want the=20 > LV to be fast, you can request it to be contiguous when creating it.=20 > Then you only get a fragment for each time it is grown. It's a price=20 > often worth paying for the flexibility. =46rom what I see, the key selling point for LVM is the ability to 'easily' add/remove/resize LVs. And then if you buy that and start to actively use these features, you end up in a situation (badly fragmented LVs) from which there isn't a proper way out. No - backup and restore, or 'have enough contiguous free space to mirror your entire LV and then nuke the original' = are not the answer. What's sad is that there isn't any fundamental technical reason LVs can't be defragmented. They can, just no one has bothered to wri= te the corresponding code yet. --=20 With respect, Roman --Sig_/VGffokO2aS/A6mEhw5mrkP6 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk3OWFsACgkQTLKSvz+PZwj8bwCfdMlEdBrqM8uuPJCnTBQwVm41 Op8An2o2EwlxbKTRWUzJY6/cfhOKett7 =xJOL -----END PGP SIGNATURE----- --Sig_/VGffokO2aS/A6mEhw5mrkP6--