[ale] Ubuntu Linux Defrag EXT4

Ron Frazier atllinuxenthinfo at c3energy.com
Mon Sep 13 12:03:07 EDT 2010


Michael,

Sorry your original email crashed.  Thanks for this info.  That looks very 
interesting, and I'm going to save the link for later examination.  I don't 
have the luxury of using multiple partitions / drives on the computers I 
use, however, it sounds like a great idea.  You seem to be very 
knowledgeable, so I'm coming to you if I have more serious questions on the 
topic.  8-)

Ron

At 9/13/2010 12:29 AM -0400, you wrote:
>On Sat, Sep 11, 2010 at 10:01 PM, Ron Frazier 
><<mailto:atllinuxenthinfo at c3energy.com>atllinuxenthinfo at c3energy.com> wrote:
>I am interested in what everyone thinks as to the need for defrag on EXT4
>in Linux vs the need for it with NTFS and Windows.
>
>
>I had written a fairly lengthy post on this only to have it eaten before I 
>hit "Send".  Grr.
>
>A good place to start reading is the Wikipedia article on filesystem 
>fragmentation 
>(<http://en.wikipedia.org/wiki/File_system_fragmentation>http://en.wikipedia.org/wiki/File_system_fragmentation) 
>which provides a good overview of the subject.  Like anything on 
>Wikipedia, you can spend hours upon hours reading there.
>
>Without going to a great deal of effort (we just got back from Toledo and 
>I am about ready to have a long, long sleep), operating systems such as 
>DOS and Windows require filesystem defragmentation as a matter of routine 
>operation.  The problem could be mitigated somewhat if different types of 
>files were on different filesystems (e.g., if C:\, C:\Windows, C:\Users, 
>C:\Program Files and C:\Program Files (x86) were all their own 
>partitions), because then updates to the operating system or user profiles 
>would have no effect on each other.  This is one reason why a UNIX system 
>with multiple partitions does not suffer (as much) from the symptoms of 
>file fragmentation.  Furthermore, if you can put filesystems that are 
>likely to suffer a great deal of fragmentation on their own drives, you 
>can reduce the symptoms even further.
>
>I've never even thought to check fragmentation on my drives at home, nor 
>on the small business servers that I run; filesystem I/O is not a problem 
>on my systems in that regard.  I do keep things heavily separated and 
>partitioned, and I try hard to keep temporary data on RAM disks instead of 
>real filesystems.  If I do need a large amount of temporary storage on a 
>system, I'll give it its own dedicated filesystem instead of having it 
>share a mount point with the root filesystem or similar; I've always found 
>it to be good practice to keep partitions separated from each other by 
>functional task.  Not only does it mean that fragmentation isn't a problem 
>across those filesystems, but it means that it's easy to work with backing 
>up and restoring an individual filesystem based on its purpose (and since 
>some filesystems change less frequently than others, it is somewhat easier 
>to back up data efficiently).
>
>Anyway, that's really all I've the energy to spew forth tonight.  Of 
>course, if you're interested, there is _plenty_ out there to search about 
>and read up on.  I'd recommend starting with learning about relatively 
>simple filesystems like the FAT family, and then research progressively 
>more complex filesystems and what functionality they provide.  Then start 
>looking into various different implementations of those filesystems 
>(usually, operating system kernels) to see how they combat (or ignore!) 
>the problems of filesystem fragmentation and other filesystem agnostic issues.
>
>Filesystems can be a very fascinating thing to learn about...


--------------------------
(PS - If you email me and don't get a quick response, you might want to 
call on the phone.  I get about 300 emails per day from alternate energy 
mailing lists and such.  I don't always see new messages very quickly.)

Ron Frazier

770-205-9422 (O)   Leave a message.
linuxdude AT c3energy.com
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