[KLUG Members] Defrag'ing ext3 filesystems?

[Adam Williams]

>>>Okay, all the usenet messages I've been reading about ext2/3 not needing
>>>to be defragmented are full of crap!
>>*I* didn't say that. 
>I didn't say _you_ did.  :-)   But a lot of others did.

Yep, I've read that lots of times.  Apparently by people who don't
wonder why their file-server IS SO SLOW.

>>>Yesterday when I was downloading the ISO images for Redhat 8.0,
>>>I was running two downloads at once, saving to the same partition.
>>>This is sure to fragment the ISO images, but no problem, at
>>>least according to the messages I've been reading in usenet...
>>How long has this file system been around?
>I don't know, but it doesn't get used a lot and doesn't contain 
>a lot files.  Mainly just a few big files I download off 'da net.

Successive create/deletes seem to be the speediest path to
fragmentation.  It still usually takes awhile, but ext2/3's block
allocation scheme ain't so swift.  

XFS uses delayed allocation (Hey! It's already in the journal anyway,
right?) and a b-tree table of available blocks to push out the
inevitable onset of fragmentation.

And when it gets fragmented?  No problem.  Just use at to schedule a run
of xfs_fsr.  Kick back and watch the tele.

>>>I've seen some defragment programs for ext2.  Does anyone know if they
>>>work on ext3?
>>You'd have to convert your ext3 back to ext2, defragment, and then
>>convert back to ext3.
>>But the defrag program has been pulled from the ext2/3 website. :(
>That doesn't sound good.

My opinion too.  Thats why I stopped using it.

>>>Adam:  Checking the KLUG mailing list archives, I saw you had a defrag
>>>program on your AWware CD of a couple years ago.  Has that been updated
>>>for ext3?  What is the URL for it?  I haven't been able to locate it.
>>http://www.rpmfind.net//linux/RPM/contrib/libc6/i386/defrag-0.73-5.i386.html
>I saw that one, but it has a slightly different filename than the one on
>your CD.  I downloaded it anyway, and looked at the RPM header in hopes
>of finding the home page, but it contained nothing useful.

Yep.

The name is different but I think they came from the same (now removed
from public consumption) source tree.

>>I haven't used it in awhile,  I don't know how much it will like newer
>> 2.4.x kernerls.  It certainly knows nothing about ext3 filesystems.
>I probably won't chance it.  Now that I know how severe this can be,
>I'll be more careful when downloading big ISO images.
>>Want to start making BS-Ware PRO again?
>I take it your opinion of ReiserFS hasn't improved?  :-)

Yes.

>The thing I don't like about BSware-PRO is being dependent on SGI.
>Has SGI released their XFS installer/kernel for RH 8.0?  I doubt it.

Nope, no installer yet for 8.0,  just 7.3.  It will be interesting to
see how long it takes.

>When a kernel security advisory is issued, I have to wait weeks for SGI
>to come out with their patched kernel.  Plus updating from from one
>release of Redhat to a newer one doesn't work.  XFS itself is good, but
>adding to BSware is a pain.

All true. :(

>Hopefully that'll change in future releases of Redhat.  Didn't I
>recently read that XFS has been merged into the 2.5.x kernel?

Yes. But who knows when 2.6.x will actually appear.  I've heard no
rumors of a coming feature freeze.