Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
Some ext3 Filesystem Tips
View unanswered posts
View posts from last 24 hours

Goto page Previous  1, 2, 3, 4 ... 13, 14, 15  Next  
Reply to topic    Gentoo Forums Forum Index Documentation, Tips & Tricks
View previous topic :: View next topic  
Author Message
jdgill0
Veteran
Veteran


Joined: 25 Mar 2003
Posts: 1366
Location: Lexington, Ky -- USA

PostPosted: Tue May 17, 2005 3:21 am    Post subject: Reply with quote

syrrus,

It seems I am misunderstanding a few things with immutable. Adding acl to my fstab for my /home partition does let root chattr +i somefile, but only root can do this. Also, I was under the impression with ext2,3 that once the immutable bit was set, the file could not be deleted, i.e. could not rm somefile, until the immutable bit was unset. I was able to remove the file with the immutable bit set in my reiserfs file. I thought that was the point of immutable, to not be able to remove the file with that bit set -- only reading or appending the file was allowed. Lastly, I did not think the immutable with ext2,3 was an ACL thing, that it was built into the ext2,3 filesystem?

[EDIT]
I have done some more playing with chattr and lsattr. Under the reiserfs filesytem it "appears" I can set the various bits, however it also appears they hold no meaning, as I can still do whatever I want to the files as root or user that I want regardless of what bits have been set. Unfortunately I do not have an ext2,3 filesystem to play with.
_________________
Vim has excellent syntax highlighting for configuration files: emerge gentoo-syntax
Learn how to use Vim: vimtutor


Last edited by jdgill0 on Tue May 17, 2005 3:37 am; edited 2 times in total
Back to top
View user's profile Send private message
syrrus
n00b
n00b


Joined: 16 May 2005
Posts: 24
Location: College Station, TX

PostPosted: Tue May 17, 2005 3:34 am    Post subject: Reply with quote

Ok, acl and immutable are completely different. ACL is access control list, thats just a major enhancement to rwx.
The file system flags mantained by chattr are just like the BSD ones that interact with the Secure level. Now if you
chattr +i the file is immutable but just a simple chattr -i can just make that entire concept null. Using th BSD secure
level implementation for linux accually enforces the rules you set by the file.
_________________
Gates Closed,
Windows Broken,
I Found the Source;
And It Was Open.
Back to top
View user's profile Send private message
jdgill0
Veteran
Veteran


Joined: 25 Mar 2003
Posts: 1366
Location: Lexington, Ky -- USA

PostPosted: Tue May 17, 2005 3:40 am    Post subject: Reply with quote

syrrus,

See my [EDIT] that I added to my last post -- guess I was too slow :( ... anyways, as I said in the edit, it seems to me the chattr bits do nothing under reiserfs from what I can see. Setting chattr +i somefile or even chattr +u somefile (for undeleteable) does not change what I can or can not do to the files, although lsattr somefile clearly shows the bits set.

[EDIT]
I was able to setup an ext3 partition. Under ext3 the immutable bit works as I was expecting it too -- i.e. the file can not be deleted until the immutable bit is unset. Which now brings me back to my original point --> as an example, setting the immutable bit on config files that you modify would help keep you from overwriting them with an etc-update by accident. However, I am still not sure why non-root users should not be allowed to use chattr, as it seems it could be useful to normal users to keep from deleting important files of their own. All the useful things I have seen with ext3, and the compatibility of programs to modify/recover from ext3 is certainly moving me a lot closer to switching from reiserfs to ext3.

[EDIT 2]
(I add this bit just to clear up the confusion on chattr/lsattr with reiserfs)
You can use the BSD levels (i.e. chattr and lsattr) with reiserfs. To do so, you must use the attrs mount option.

I originally posted about chattr/lsattr for ext3 thinking it might be of interest to those who are looking to use ext3, but I wasn't sure if it fit in with codergeek's ext3 howto in this thread.
_________________
Vim has excellent syntax highlighting for configuration files: emerge gentoo-syntax
Learn how to use Vim: vimtutor


Last edited by jdgill0 on Tue May 17, 2005 4:57 pm; edited 1 time in total
Back to top
View user's profile Send private message
syrrus
n00b
n00b


Joined: 16 May 2005
Posts: 24
Location: College Station, TX

PostPosted: Tue May 17, 2005 12:11 pm    Post subject: Reply with quote

Most likely the bit's are not obeyed until the BSD secure level is elevated. I will experiment on one of my newer installs and see exactally whats happening.

[This thread isn't exactally the best place to continue this conversation. Feel free to PM me so we can do some more research]
_________________
Gates Closed,
Windows Broken,
I Found the Source;
And It Was Open.
Back to top
View user's profile Send private message
tcostigl
Tux's lil' helper
Tux's lil' helper


Joined: 28 Jul 2004
Posts: 97

PostPosted: Wed May 18, 2005 1:18 am    Post subject: Reply with quote

I assume this would also apply to a software raid partition(md raid) on /dev/md* formatted with ext3.
Back to top
View user's profile Send private message
Juzna
n00b
n00b


Joined: 03 Jul 2004
Posts: 3

PostPosted: Sat May 21, 2005 3:03 pm    Post subject: Reply with quote

I just wonder if I can change to full journal without any downtime on my server, with -o remount handle. Will this break my fs or can I do it?
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Sat May 21, 2005 4:55 pm    Post subject: Reply with quote

tcostigl wrote:
I assume this would also apply to a software raid partition(md raid) on /dev/md* formatted with ext3.
I've no experience with that but since the tune2fs/e2fsck tools operate on the filesystem itself, it should work just fine on RAID disks or other media which use the ext2 or ext3 filesystem.
juzna wrote:
I just wonder if I can change to full journal without any downtime on my server, with -o remount handle. Will this break my fs or can I do it?
I just tried it, and my kernel gave me an error saying I couldn't do that:
Quote:
EXT3-fs: cannot change data mode on remount
This was trying to remount my /usr/portage with 'data=ordered'. Unmounting it, then mounting it with 'data=ordered' works just fine though, so what you're trying to do does not seem possible.
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
fallow
Bodhisattva
Bodhisattva


Joined: 08 Jan 2004
Posts: 2206
Location: Poland

PostPosted: Mon May 23, 2005 7:50 am    Post subject: Reply with quote

good to see this how-to here :) maybe more and more users will see the goodies in lower cpu usage and better interactivity of rest of the system in thanks to it ;) [ in comparision to reiser* ] .

I personally using dir_index feauture and writeback mode. Yeah I like less journalling , full journalling for example gives me too higher cpu usage with filiesystems RW operations.

cheers & thanks & greetings :)
_________________
"Time is a companion that goes with us on a journey. It reminds us to cherish each moment, because it will never come again. What we leave behind is not as important as how we have lived" J-L. Picard ;)
Back to top
View user's profile Send private message
darklegion
Guru
Guru


Joined: 14 Nov 2004
Posts: 467

PostPosted: Tue Jun 07, 2005 2:29 am    Post subject: Reply with quote

codergeek42 wrote:
@prymitive: You can adjust your block size and inode count when you initially create the filesystem. Setting it to use 1KB block sizes and 1 inode per 1KB should give you the most effecient space usage:
Code:
# /sbin/mkfs.ext3 -b 1024 -i 1024 /dev/hXY
Be warned though that decreased the block size and increasing the inode allocation in this manner can cause a significant performance decrease if the filesystem is store larger files as well (since it has to do more journalling, I/O, and resource allocation).


I tried this out and the results were not at all promising.Listed here is the freespace before and after changing the block size/inode count:
Code:

Before:
/dev/hdc               74G   33M   74G   1% /nxbox
After:
/dev/hdc               66G  8.1M   62G   1% /nxbox


Well at least the journal is skightly smaller *laughs*.I'm guessing that larger drives are designed to work with larger blocksizes although I don't know if you can call an 80gb drive *large* anymore.
Back to top
View user's profile Send private message
darklegion
Guru
Guru


Joined: 14 Nov 2004
Posts: 467

PostPosted: Tue Jun 07, 2005 2:29 am    Post subject: Reply with quote

codergeek42 wrote:
@prymitive: You can adjust your block size and inode count when you initially create the filesystem. Setting it to use 1KB block sizes and 1 inode per 1KB should give you the most effecient space usage:
Code:
# /sbin/mkfs.ext3 -b 1024 -i 1024 /dev/hXY
Be warned though that decreased the block size and increasing the inode allocation in this manner can cause a significant performance decrease if the filesystem is store larger files as well (since it has to do more journalling, I/O, and resource allocation).


I tried this out and the results were not at all promising.Listed here is the freespace before and after changing the block size/inode count:
Code:

Before:
/dev/hdc               74G   33M   74G   1% /nxbox
After:
/dev/hdc               66G  8.1M   62G   1% /nxbox


Well at least the journal is slightly smaller *laughs*.I'm guessing that larger drives are designed to work with larger blocksizes although I don't know if you can call an 80gb drive *large* anymore.

EDIT: I forgot to enable -m0 to get rid of the superuser-reserving-space buillshit,which gave me 66gb but that is still significantly smaller.
Back to top
View user's profile Send private message
torchZ06
Apprentice
Apprentice


Joined: 01 Nov 2003
Posts: 175
Location: the front range

PostPosted: Thu Jun 16, 2005 9:00 pm    Post subject: Reply with quote

codergeek42 wrote:

There are two different ways to activate journal data mode. The first is by adding data=journal as a mount option in /etc/fstab. If you do it this way and want your root filesystem to also use it, you should also pass rootflags=data=journal as a kernel parameter in your bootloader's configuration. In the second method, you will use tune2fs to modify the default mount options in the filesystem's superblock:

am i correct in interpreting this statement as meaning if you're running a new kernel and set the flags in the superblock that you DON'T have to add anything to /etc/fstab or your grub.conf in order to take advantage of journal data mode?

is there some way to see what mount options are being used-- not reading the superblock with tune2fs, but rather to actually see what mount is using?
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Thu Jun 16, 2005 9:27 pm    Post subject: Reply with quote

torchZ06 wrote:
am i correct in interpreting this statement as meaning if you're running a new kernel and set the flags in the superblock that you DON'T have to add anything to /etc/fstab or your grub.conf in order to take advantage of journal data mode?
That's correct. The flags in the superblock are default mount flags. Unless you specify otherwise (via command-line options or /etc/fstab), those options will always be used when mounting.
Quote:
0is there some way to see what mount options are being used-- not reading the superblock with tune2fs, but rather to actually see what mount is using?
You can check your kernel log with `dmesg` and you should see sometrhing similar to the following for each Ext3 partition:
Code:
$ dmesg
[...]
EXT3 FS on hda3, internal journal
EXT3-fs: mounted filesystem with journal data mode.
EXT3 FS on hda5, internal journal
EXT3-fs: mounted filesystem with journal data mode.
[...etc...]
Hth!
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
mauricev
Tux's lil' helper
Tux's lil' helper


Joined: 22 Mar 2004
Posts: 107

PostPosted: Sat Jun 18, 2005 7:27 pm    Post subject: Is this statement accurate? Reply with quote

codergeek42 wrote:
You don't need to defragment ext2/ext3 because as you use the filesystem file blocks and inodes are moved around and reallocated to keep the data nearly contiguous. It's not perfect, but it works fairly well and you should almost never see a performance degradation caused by the filesystem's fragmentation.


I posed this statement to the ext3 mailing and asked if it were true. One of the ext3 developers, Theodore Ts'o, responds...

No, not true. (At least not today)

Ext2/3 has advanced algorithms to make sure that the blocks that are allocated avoid fragmentation, but it is not doing any kind of dynamic moving of blocks/inodes.

(At least, not yet; there has been some talk about creating enough kernel hooks so that a user-space program could do dynamic defragmentation of the filesystem, but none of this exists at the moment.)

- Ted
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Sun Jun 19, 2005 3:15 am    Post subject: Reply with quote

Hmmm I thought Ext3 did dynamic reallocation like that but I guess not. It still kicks butt as an excellent FS anyhoo. :wink: Thanks, mauricev. :oops:

EDIT: Link to message: https://www.redhat.com/archives/ext3-users/2005-June/msg00026.html
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF


Last edited by codergeek42 on Fri Sep 02, 2005 8:21 pm; edited 1 time in total
Back to top
View user's profile Send private message
blaster999
l33t
l33t


Joined: 09 May 2004
Posts: 902
Location: Between keyboard and chair

PostPosted: Tue Jun 28, 2005 2:15 pm    Post subject: Reply with quote

Hi codergeek42, great guide! I think I'm gonna dump my reiser3.6 partition and switch to ext3. One question (a little OT): is there a FS which actually does full dynamic relocation?
_________________
60s: sex, drugs, rock'n'roll
90s: sux, bugs, drag'n'drop
---
Some multimedia keys refuse to work? See my mini-howto:
http://forums.gentoo.org/viewtopic.php?p=1896734#1896734
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Tue Jun 28, 2005 4:05 pm    Post subject: Reply with quote

blaster999,

I think Reiser4 is supposed to use dancing trees to achieve this. I'm not too sure, however, if that's for the file data or purely the metadata or what it's for, as I've not read too much about it.
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
m0p
Apprentice
Apprentice


Joined: 20 Jun 2005
Posts: 205
Location: en_GB

PostPosted: Thu Jun 30, 2005 10:03 pm    Post subject: Reply with quote

I'll try these tweaks tomorrow cause I'm going to bed soon. Another ext3 fan here too :)
Back to top
View user's profile Send private message
fbvortex
n00b
n00b


Joined: 01 Jul 2005
Posts: 22

PostPosted: Fri Jul 08, 2005 3:55 am    Post subject: rootflags=data=journal Reply with quote

Has anyone here successfully used the rootflags=data=journal kernel command-line parameter for their root partitions? If so, after boot, what does a listing of the "mount" command show for / ? On my setup, after having done that, a mount listing does not show data=ordered in the mount listing for / .

The kernel message log does show that rootflags=data=journal is getting passed in.

How can I tell if / is correctly being mounted with data=journal when it goes rw?
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Fri Jul 08, 2005 4:16 am    Post subject: Re: rootflags=data=journal Reply with quote

fbvortex wrote:
How can I tell if / is correctly being mounted with data=journal when it goes rw?
You should see something like the following in your kernel log:
Quote:
EXT3-fs: mounted filesystem with journal data mode.
VFS: Mounted root (ext3 filesystem) readonly.
EXT3 FS on hda3, internal journal
When it remounts it as read/write no messages seem to appear in my kernel log. I don't use the "rootflags=data=journal" method though, since I use tune2fs to set the default mount option in my filesystems' superblocks.
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
fbvortex
n00b
n00b


Joined: 01 Jul 2005
Posts: 22

PostPosted: Fri Jul 08, 2005 4:35 pm    Post subject: Reply with quote

codergeek42,

Can you tell me what the output of 'mount' (without any options) is for your / filesystem? I'd like to see if the data=journal is supposed to show up there.
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Sat Jul 09, 2005 4:04 am    Post subject: Reply with quote

fbvortex wrote:
codergeek42,

Can you tell me what the output of 'mount' (without any options) is for your / filesystem? I'd like to see if the data=journal is supposed to show up there.
Sure.:
Code:
$ mount | grep hda3
/dev/hda3 on / type ext3 (rw)
And the superblock information:
Code:
tune2fs 1.37 (21-Mar-2005)
[...]
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal dir_index filetype needs_recovery sparse_super
Default mount options:    journal_data user_xattr
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
[...]

_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
chevelle
n00b
n00b


Joined: 01 Apr 2004
Posts: 19

PostPosted: Tue Jul 12, 2005 3:14 am    Post subject: Reply with quote

dig it

Last edited by chevelle on Thu Jul 14, 2005 5:45 am; edited 1 time in total
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Tue Jul 12, 2005 3:12 pm    Post subject: Reply with quote

Err...you have backups I hope? :? I don't know if those errors are fixable...
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
alari
n00b
n00b


Joined: 23 Feb 2004
Posts: 47
Location: Tartu, Estonia

PostPosted: Sun Jul 24, 2005 5:18 pm    Post subject: Reply with quote

Is the information in the first post up-to-date ?
I'm gonna do a reinstall on my syste, i have used reiser4 for about 18months or so and it's damn slow, (i dont have time to mess with the repacker, heard to be seen in reiser4.1)
Can i use the tips in the first post, after i format my partitions with ext3 during the install ?
Back to top
View user's profile Send private message
codergeek42
Bodhisattva
Bodhisattva


Joined: 05 Apr 2004
Posts: 5142
Location: Anaheim, CA (USA)

PostPosted: Sun Jul 24, 2005 6:08 pm    Post subject: Reply with quote

alari wrote:
Is the information in the first post up-to-date ?
I'm gonna do a reinstall on my syste, i have used reiser4 for about 18months or so and it's damn slow, (i dont have time to mess with the repacker, heard to be seen in reiser4.1)
Can i use the tips in the first post, after i format my partitions with ext3 during the install ?
Yes, the information is up-to-date to my knowledge. I'm using kernel 2.6.12-gentoo-r6 with e2fsprogs version 1.38.
_________________
~~ Peter: Brony, GNU/Linux geek, caffeine addict, and Free Software advocate.
Who am I? :: EFF & FSF
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Documentation, Tips & Tricks All times are GMT
Goto page Previous  1, 2, 3, 4 ... 13, 14, 15  Next
Page 3 of 15

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum