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#1 2009-01-17 20:34:54

ssl6
Member
From: Ottawa, ON, CA
Registered: 2007-08-30
Posts: 594

ext4

so i've been keeping an eye on ext4 for a couple of weeks since i heard about it. now my understanding, is that ext4 support requires the 2.6.28 kernel i just updated to yesterday i think right?

now, i understand that an ext3 filesystem can be mounted as ext4 without conversion. so my question with that, is i assume that gives me the ability to modify fstab, run mount -u for example and make sure it still mounts?

and then i can proceed with the conversion, after backing up of course. i found this command for the conversion in another thread here, would this be the recommended method?

$ sudo tune2fs -l /dev/hdd1 | grep features
Filesystem features:      has_journal resize_inode dir_index filetype needs_recovery extent sparse_super large_file uninit_bg

this is a signature

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#2 2009-01-17 21:59:48

LTSmash
Member
From: Aguascalientes - Mexico
Registered: 2008-01-02
Posts: 348
Website

Re: ext4

Why don't you read this?

http://wiki.archlinux.org/index.php/Ext4

You can mount an ext3 partition with ext4, and you'll get some of the nice new stuff, you can also convert your ext3 partition or make an ext4 one which will be compartible with ext3, but you won't be getting everythingif you don't use an ext4 partition with extents, which will render incompartible the partition with ext3 or older.

To get it clear:
Meanwhile you do NOT use extents, your partition will be backwards compartible. That's it.


Proud Ex-Arch user.
Still an ArchLinux lover though.

Currently on Kubuntu 9.10

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#3 2009-01-31 21:28:00

Raccoon1400
Member
From: Ontario, Canada
Registered: 2008-04-14
Posts: 853

Re: ext4

I just switched to ext4. It took about 3 sec off my boot.
Here's how I familiarized myself with the procedure:
-converted my vbox arch install
-converted a partition I was trying to install lfs on, on my real hard drive, to make sure arch could still read it
-the real thing

The vbox test told me exactly what to expect. I have everything on one partition, no seperate /var, or /home, so it was all or none.


Fustrated Windows users have two options.
1. Resort to the throwing of computers out of windows.
2. Resort to the throwing of windows out of computers.

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#4 2009-02-01 09:19:56

vertana
Member
Registered: 2009-01-31
Posts: 26

Re: ext4

I also, switched my root partition to ext4 just a few days. I had to hard reboot my computer once as well and no data was corrupted. I do not have seperate partitions for /boot or /home, but I've had no problems at all and my boot speed dropped about 2 seconds as well. Good luck, but as always YMMV smile

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#5 2009-02-01 23:06:06

fukawi2
Forum Moderator
From: .vic.au
Registered: 2007-09-28
Posts: 5,296
Website

Re: ext4

umount /mnt/disk
mount -t ext4 /mnt/disk

Assuming:
1. /mnt/disk is an existing exty3 partition
2. /mnt/disk is in fstab
3. You don't want to use it as an ext3 partition again.
As mentioned, this won't take advantage of extents for your existing data, but new data will be allocated extents (AFAIK).

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#6 2009-02-02 02:34:52

Ranguvar
Member
From: Our collective subconscious
Registered: 2008-08-12
Posts: 2,515
Website

Re: ext4

^^ http://wiki.archlinux.org/index.php/Ext … t3_to_ext4

What you described will not do a full convert, you can use ext3 again. And, you won't lose just extents, you'll lose multiblock/delayed allocation, plus maybe more, as the wiki says. tune2fs and fsck are needed to get those features, at which point you lose backwards-compatibility. Extents are then created for new data, too, but not for old stuff, as you said. e4defrag can make old stuff have extents, but it's been discussed and problems are likely.

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#7 2009-02-02 06:07:01

fukawi2
Forum Moderator
From: .vic.au
Registered: 2007-09-28
Posts: 5,296
Website

Re: ext4

OK, I stand corrected... The article I read about it said it wouldn't be able to go back to ext3 after doing that. I just tested and you can. Ignore my post, Ranguvar is correct.

Last edited by fukawi2 (2009-02-02 06:07:22)

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#8 2009-02-02 12:07:38

vertana
Member
Registered: 2009-01-31
Posts: 26

Re: ext4

What do extents do for your old data? Is it worth the risk involved? (I haven't used e4defrag, but only because I'm not sure what beneifts extents would have on old data)

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#9 2009-02-02 12:16:35

Ranguvar
Member
From: Our collective subconscious
Registered: 2008-08-12
Posts: 2,515
Website

Re: ext4

vertana wrote:

What do extents do for your old data? Is it worth the risk involved? (I haven't used e4defrag, but only because I'm not sure what beneifts extents would have on old data)

It makes your data go vroom.

There was a thread a while back. I posted a few benchmarks that I found.

Here ya go.

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#10 2009-02-02 23:41:19

vertana
Member
Registered: 2009-01-31
Posts: 26

Re: ext4

I'll be sure to try this when I get home tonight then! Cause I definitely want my data going vroom tongue

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#11 2009-02-12 13:44:35

MetalheadGautham
Member
From: Bangalore, India
Registered: 2008-07-27
Posts: 143
Website

Re: ext4

Hey, I have archlinux installed in my HDD. How do I go about the conversions ?
Shall I just edit FSTAB and change ext3 to ext4 for both /home and / ?

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#12 2009-02-12 14:08:00

b0uncyfr0
Member
Registered: 2008-05-11
Posts: 140

Re: ext4

Can someone answer my question..

Do any of these methos going from ext3 to ext4 allow my drives to remain redable in windows. I use the fs-driver to share data and its too important to lose. So will it still work with fs-driver if i change it?

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#13 2009-02-12 15:05:25

Inxsible
Forum Fellow
From: Chicago
Registered: 2008-06-09
Posts: 9,073

Re: ext4

b0uncyfr0 wrote:

Can someone answer my question..

Do any of these methos going from ext3 to ext4 allow my drives to remain redable in windows. I use the fs-driver to share data and its too important to lose. So will it still work with fs-driver if i change it?

According to the FAQ at fs-driver.org, it does not even support Ext3. The only way you can read write into Ext3 drives, is because they are mounted as Ext2 drives, since Ext3 is backwards compatible to Ext2. Again Ext4 is backwards compatible to Ext3 so they too will be mounted as ext2 drives -- of course which means that you will not get journaling or extents features


Forum Rules

There's no such thing as a stupid question, but there sure are a lot of inquisitive idiots !

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#14 2009-02-12 21:00:34

pointone
Wiki Admin
From: Waterloo, ON
Registered: 2008-02-21
Posts: 379

Re: ext4

Note that ext4 is not backwards compatible after extents have been enabled.

The method b0uncyfr0 wants is: http://wiki.archlinux.org/index.php/Ext … Converting


M*cr*s*ft: Who needs quality when you have marketing?

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