[ale] Ubuntu Linux Defrag EXT4

[Ron Frazier]

Greg,

That's good info.  Based on what I've heard up to this point, I'm 
definitely hesitant to tinker with it.  I understand that there are 3 
different journaling modes available with ext4.  I've seen conflicting 
information on what the Ubuntu default 10.04 is.  Do you know what it 
is?  And do you know a definitive way for me to determine the current 
mode?  For what it's worth, I created the partition as EXT4 when I 
installed Ubuntu from the CD.

Ron

At 9/13/2010 01:58 PM -0400, Greg Freemyer wrote:
>On Mon, Sep 13, 2010 at 11:58 AM, Ron Frazier
><atllinuxenthinfo at c3energy.com> wrote:
> > Greg,
> >
> > Thanks for the tip.  Based on other comments, I don't think I'll be
> > defragging Linux just yet.
> >
> > A few people mentioned corrupting a Linux / Unix HDD by running utilities
> > while the partition is mounted.  When I run chkdisk on my Windows system in
> > read / write mode, it pops up a dialog that says it can't run the test now
> > because the system is in use.  It offers an option to run the test the next
> > time I reboot, and I click yes or no.  Linux should offer me the same
> > courtesy, in my opinion.
> >
> > Ron
>
>e4defrag is designed to be used online (ie. with the FS mounted)
>
>I'm not sure I was clear before, but I monitor the ext4 mailinglist
>and have not seen a complaint of e4defrag causing data corruption in
>over a year (maybe 2.6.32 timeframe).  All reported bugs have been
>addressed and I believe backported to at least 2.6.32.
>
>OTOH, Ted T'so (the ext4 maintainer) has said he would like to see a
>more sophisticated test suite written for e4defrag to make sure it is
>not causing any data corruption even in unusual filesystem configs.
>
>ie. Various page sizes;  FS created as ext4;  FS converted from ext3
>to ext4; with and without journaling; FS bigger than 16 TB.
>
>So if you have a vanilla ext4 setup, you should be fine to run it
>online.  If you have something more exotic like ext4 without a
>journal, then I would personally be very hesitant.
>
>Greg


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Ron Frazier

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