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RE: 2GB of Waste? How can it be? -- sysadmin cutting in

Mr. Smith:

	I am not as concerned about fragmentation, as the bulk of the
files on the system are large (about 10GB of 16GB), and wont change, and
I need the space (it is on a laptop, and I am the only user), so I will
choose to remove the space reservation of 5%, but I agree with you in
other instances.

	It is not that I wish to see ext2/ext3 mucked with; it is that I
would prefer to use ReiserFS. However, RedHat has gone and forced upon
people EXT3 as a root filesystem. I would much prefer to install RedHat
into a ReiserFS partition, but that is not a choice. I tried to force it
to work, but that breaks other things (initrd usage, devfs mounting,

	SuSE on the other hand (which I do not care for really, so I am
not a SuSE bigot), does allow you to install to ReiserFS or EXT3 I
understand. I do not comprehend why RedHat does not allow you the same
option. That is why I am complaining about ext3. Now on the root, I
agree the 5% space reservation ought not to be removed.

	/home I have separated out, and am considering to separate out
/tmp as well. However, my log files and /usr stuff is not so big, and it
does not change much, so having them on the root is okay for me
(remember this is for a laptop, which is also why I refer to have my
/root journaled, in case the battery goes out!).

	Why ReiserFS does not work properly in RedHat as the root
filesystem is not a ReiserFS question, it is a RedHat question, since it
works fine on other Linuxes as a root filesystem, even if you use initrd
and devfs=mount, on RedHat it does not work, why? Incidentally, I do use
GRUB, not lilo.

	In terms of partition magic, I agree it is not the best way to
do things, but it is the only game in town. I know parted will resize
ext2, but I also need to resize NTFS as well sometimes. I prefer to try
to use one tool for both jobs, but I guess it is best to have both

Very Respectfully, 

Stuart Blake Tener, IT3 (E-4), USNR-R, N3GWG 
Beverly Hills, California
VTU 1904G (Volunteer Training Unit) 
stuart bh90210 net 
west coast: (310)-358-0202 P.O. Box 16043, Beverly Hills, CA 90209-2043 
east coast: (215)-338-6005 P.O. Box 45859, Philadelphia, PA 19149-5859 

Telecopier: (419)-715-6073 fax to email gateway via www.efax.com (it's


Sunday, January 13, 2002 4:38 AM

-----Original Message-----
From: bs linux-wlan com [mailto:bs linux-wlan com] On Behalf Of Bryan J.
Sent: Monday, February 04, 2002 11:00 AM
To: stuart bh90210 net
Cc: ext3-users redhat com
Subject: Re: 2GB of Waste? How can it be? -- sysadmin cutting in

[ SysAdmin, non-fs guru cutting in ]

"IT3 Stuart Blake Tener, USNR-R" wrote:
> In the instant case, I am creating a filesystem for /home
> directories, thus, a 5% reservation for root is not needed here, so I
> shall take your advice and return it to the general free space pool.

Ummm, the 5% reservation is to prevent the high levels of
fragmentation that occur when the filesystem is near full (something
that I wish Windows would adopt as standard too ;-).  It is also to
keep your system from "hanging" if system/root processes need to
write to the filesystem, so they aren't at the "mercy" of users
filling it up.  And there are a few other, very important reasons

So, I highly recommend you do _not_ remove it.  It's saved my @$$
several times when my users didn't bother to care.  ;-P

> Why cannot ext2/ext3 allocate inode space on a dynamic basis?

Before you ask that, ask yourself:
"Do I want a proven filesystem to be mucked with?  Wouldn't it be
easier to check out ReiserFS, XFS or JFS instead?"

I, for one, don't want Ext2/3 changed because I like its _proven_
reliability _and_ (more importantly) recoverability.  I'm sure
Tweedie & co. will get to more radical Ext2/3 changes (Ext4?), but
I'll take reliability and recoverability any day over features.

On that note, SGI's XFS filesystem shares much in common with Ext2/3
features (e.g., POSIX ACLs) and realibility (proven on Irix), in
addition to on-the-fly inode creation, etc...  If you want then, use
XFS.  SGI's releases for RedHat, based on the same RedHat RPMs,
allow you to use both Ext3 and XFS (as well as Ext2).

> More importantly why is it not possible to amend the number of
> inodes an ext2/ext3 filesystem has after the point of doing an mke2fs?

Again, ask yourself the above question.  ;-P

> One other question, as well:
> I modified my RedHat installation to boot up using a root
> filesystem of ReiserFS, but when I try to use devfs=mount along with
> initrd, it seems to give me some errors (initrd= something or other
> error, I will write it down next time). Any ideas?

Bit of advise for you that works well for me:  
Always make / Ext2.  You should be separating out at least /tmp,
/var, /usr and /home anyway, so / doesn't need to be that big. 
Hence, journaling is not a big deal.  If / is Ext2, I can boot any
disk and read /.

Regarding ResierFS, such questions are best for the ResierFS lists. 
There are some issues with using LILO and ResierFS as /, but GRUB
has a ReiserFS driver to overcome them.

> What command do I give to tune2fs to change the space
> reservation percentage?

_Always_ consult the oracle of man before you post ... ;-P

 $ man 8 tune2fs
 -m reserved-blocks-percentage
          Set the percentage of reserved filesystem blocks.
 -r reserved-blocks-count
              Set the number of reserved filesystem blocks.

> Also, I noticed that if I turn on ext3 journaling, I can no
> longer resize the partition with partition magic. So I am curious, how
> can completely revert an ext3 partition back to ext2 (temporarily) so
> can resize it, and then make it ext3 again. Is there a command line
> parameter for tune2fs which will reverse a "tune2fs -j"?

I believe both the FAQ and archives have answers on this.

BTW, I wouldn't trust resizing Ext2 with Partition Magic --
especially when used on newer kernels.  I've seen a number of people
getting filesystems that are barely recoverable with fsck

-- Bryan

Bryan J. Smith, Engineer        mailto:b j smith ieee org   
AbsoluteValue Systems, Inc.     http://www.linux-wlan.org
SmithConcepts, Inc.          http://www.SmithConcepts.com
1999 IRS Data:  The top 1% of income earners pay over 36%
of the taxes, but have less than 20% of the total income.

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