![]() ![]() Wrapping your head around LVM is a bit more difficult than with RAID because LVM rethinks the whole way of dealing with storage, which expectedly introduces a bit of jargon that you need to learn. LVM has undergone tremendous improvements since then and is widely used in production today, and just as you expect, the Ubuntu installer makes it easy for you to configure it on your server during installation. ![]() ![]() Through the magic of free software, a guy by the name of Heinz Mauelshagen wrote an implementation of a logical volume manager for Linux in 1998, which we’ll refer to as LVM. LVM has traditionally been a feature of expensive, enterprise Unix operating systems or was available for purchase from third-party vendors. Very cool, and very doable via logical volume management (LVM), a system that shifts the fundamental unit of storage from physical drives to virtual or logical ones. Then we could have partitions that are trivially resizable or that can span multiple drives, we could easily take some space from one partition and tack it on another, and we could juggle partitions around on physical drives on a live server. What we’d really want is a way to push the partition concept up one level of abstraction, so it doesn’t operate directly on the underlying physical media. It’ll do wonders for your worries about performance and fault tolerance, but it operates at too low a level to help with the partition size or fluidity concerns. This article is excerpted from the newly published book The Offical Ubuntu Book, Third Edition published by Prentice Hall Professional, June 2008, Copyright 2008 Canonical, Ltd. And if you might have to move a partition across physical volume boundaries on a running system, well, woe is you. As if worrying about speed and data loss weren’t enough, you also have to worry about whether your partition size calculations were just right when you were installing a server or whether you’ll wind up in the unenviable position of having a partition run out of space, even though another partition is maybe mostly unused. Hard drives are slow and fail often, and though abolished for working memory ages ago, fixed-size partitions are still the predominant mode of storage space allocation. ![]()
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