Defragmentation of Linux Filesystems

polishlinux.org

12 points·maurycy··6 comments

I don't know. All that effort, and I'm not even sure the quoted improvement is outside the error of measurement. The author doesn't specify the hardware here either, and the sustained rate of 15MB/s (peak: <35MB/s) seems to me like it's fairly old. His graphs are anything but convincing: need better data.

Really, the best thing you can do to improve your HDD performance is to:

1. Throw out ext3 and replace it with a better file system - consensus seems to be XFS if you have lots of large files, Reiser if you have lots of small ones or JFS for a nice blend. I personally have been using JFS for pretty much everything for a few years.

2. Buy a better hard disk. Good SATA disks are blazing fast these days. Get a Serial Attached SCSI RAID if the lack of speed is costing you money.

Also, ZFS (http://en.wikipedia.org/wiki/ZFS) might be worth looking into.

As far as I know, there's no ZFS support in the mainstream Linux distributions at the moment, although I admit I haven't looked into it. To be honest, I'd probably only use it in anger once they GPL it and it goes into either the mainline kernel or it at least is adopted by a commercial distribution. Of course, on Solaris, go knock yourself out. :)

Indeed, no ZFS support in major linux distributions due to licensing issues. FreeBSD has support for it though.

One way of defragging your files: moving all your content over to a fresh partition and moving it back equates to a completely unfragmented file system.

Another more important question, does the extra fragmentation actually affect performance and how does fragmentation behave over time (as linux file systems tend to de-fragment themselves during use)?

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