Last month when publishing Fedora 15 vs. Ubuntu 11.04 benchmarks in some of the disk workloads the Fedora Linux release was behind that of Ubuntu Natty Narwhal. Some users speculated in our forums that SELinux was to blame, but later tests show SELinux does not cause a huge performance impact. With Security Enhanced Linux not to blame, some wondered if Fedora's use of LVM, the Logical Volume Manager, by default was the cause.
Fedora uses a Logical Volume Manager (see the Wikipedia page for details) layout by default with its current use of the EXT4 file-system. Most Linux distributions do not setup an LVM layout by default, but here's some benchmarks of Fedora 15 with and without LVM. The Linux Logical Volume Manager is more of interest to larger enterprise environments where you may be interested in adding/replacing/removing disks and sharing the file-system contents across disks without interrupting service. Of use to many is LVM's ability to resize disk partitions as needed along with dynamic volume resizing as well as the ability to create LVM snapshots.
This LVM benchmarking is of a clean Fedora 15 DVD 32-bit installation on a Lenovo ThinkPad T60 with Intel Core Duo T2400 processor and SATA 5400RPM HDD with 1GB of system memory, ATI Radeon Mobility X300 graphics, and Intel i9145 + ICH-7M motherboard. The Fedora install used the Linux 18.104.22.168 kernel, GNOME Shell 3.0.1, X.Org Server 1.10.1, xf86-video-ati 6.14.99, Mesa 7.11-devel, GCC 4.6.0, and an EXT4 file-system.
For the Fedora 16 release, Red Hat is looking at using the Btrfs file-system by default on new installations. When this happens, they are looking to use the volume management capabilities that are apart of the Btrfs file-system rather than layering LVM on top of that too. When using EXT4, however, LVM still should be found in use.
Here's the results for this simple disk testing of performing two clean installations of Fedora 15, with and without LVM. The partition layout was the same as were all other settings. Benchmarking was carried out in an automated manner by the Phoronix Test Suite.