Alright, i'm talking to a friend who'se installing gentoo, and i got into an argument over this. It has to do with file systems for the /boot folder.

he has /boot in a different partition, with ext2 as his FS. I can understand why you'd have /boot in a different partition. My question is, must it be ext2?

From what i know, a FS is a FS, and ext3 is better than ext2 in terms of journalising, no data loss, no fragmentation etc.. and i'd be damned to stick my /boot in something which doesnt act like ext3....

In every slackware system i've installed on every computer, /boot is on my / partition, which is ext3. Which means that the /boot folder is ext3

Is there really a difference if i choose /boot to be ext2 or ext3?

I really don't know, heck, why not make /boot reiserFS? I wouldn't really notice any speed difference or anything like that. This even goes back to old WindowNT4 configurations, where the C: partition would be fat16, and where the OS itself would reside in an NTFS partition. Though after NT4 Fat32 is supported, but really you could then choose Fat16, Fat32 or NTFS to boot off of, it wouldn't really matter much, I guess it would be a matter of preference, assuming of course your friend is not having the OS sit on an XFS partition, and he doesn't want to boot from XFS, since you can't have a superblock on XFS for some reason (I don't know why, but I just remember seeing the superblock option in the Slackware setup and it said that XFS should not be used to install lilo on XFS superblock). I personally would just leave /boot on a Reiser partition, even if the os itself would be on the same FS, just having two partitions, though, one small Reiser partition just for booting off of, and another for the os itself.

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Is there really a difference if i choose /boot to be ext2 or ext3?
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the files in /boot are used only at boot, and if it's a separate partition,
it'll be very small.
so " faster " access or faster checking can't be a reason to choose one or the other.

but i wouldn't be suprised if your friend read somewhere on a gentoo forum
that ext2 is " much faster " and thus a musthave.

egag

it's not that it MUST be ext2, there's just no benefit of having it as ext3. ext3 is just ext2 + journal. now a properly managed /boot would NOT be mounted at boot, and not used as part of a healthy system, it is only accessed at boot time, directly by the boot loader to get a boot image and maybe an initrd. consequently the journal is never used, and just wastes space and provides absolutely no benefit whatsoever.

And we're talking about how much of a speed increase? or how much of time wasted?

I mean it just doesn't make sense to me Or is this the gentoo phillosophy of going through every possible detail there is?

EDIT:
Plus anyway, isn't ext2 a bit old now? I mean speed or no speed, you'd might as well tell me to go back to DOS coz its faster (exaduration).. if you see what i mean

xushi

Can't comment on the ins and outs of ext2 versus ext3 but what I can say is that I have 2 Gentoo systems

System 1
Gentoo 2005.0, 2 x SATA Western Digital Raptor Hard Drives, software raid0, separate boot partition ext2

System 2
Gentoo 2005.0, 2 x SATA Western Digital Raptor Hard Drives, software raid1, separate boot partition ext3

System one I followed a tutorial, hence ext2
System two I made my own choices, hence ext3

Both work flawlessly

Pete

Heh, well, this was what i was agreeing with.. I don't find a problem at all, and you can technically say all you want that ext2 is faster than ext3 etc.... but its just not worth it..

The gentoo guys insisted otherwise.. but anyway, i don't want this to be any sort of flamewar.. i got my answer.

Thanks.

There's no reason at all that they both won;t work fine.. because they are THE SAME THING. you are not making changes to /boot therefore the journal has nothgin to do. therefore they are aacting exactly the same. there is NO speed benefit anywhere, because it's not until the /boot partition has totally finished serving it's purpose that it's even possibel to write to it and therefore use the journal.

ext2 isn't "old", it's just superceded where beneficial, and it's not beneficial to use ext3 here at all.

I always use ext3. It has much better support than reiser.

okay, the reason to use ext2 instead of ext3 on your boot partition is...

WASTE OF SPACE! your boot partition should be pretty small, and on mine a 32 mb journal would waste half of my space I could use for kernels. ext3 and reiserfs would be complete overkill, you'd waste space and never see the benefit

Hello,

I believe that some distro's do not have ext3 support built into the kernel, so they can only access the boot partition and initrd image until the ext3 modules is loaded.

That is why some distro's create the /boot partition as ext2.

Michael

when you're loading the kernel, and fs support is in that same kernel,
how can the program that's reading it from disk have any knowledge about the fs. ?

it doesn't.
the fs support ( compiled in or in an initrd ) is used first when the kernel mounts the "/" partition.
and the kernel loader does it's work with raw disk access afaik.
( reading sectors rather than files )

egag

HUH ?? I do not understand your post ...

First, modules can get loaded automatically depending on there need, for example the other day I was playing with CentOS 4 server (not by choice) and had some trouble with the kernel. The system was using grub and had the following:

/boot ext2 (built in)
/swap
/ ext3 (by module)

So at first I told the system to load the default kernel with out using the default initrd.img file, the kernel would start booting the system, mount the boot parition but fail in mounting the root partition because the ext3 module was located in the initrd.img which is on the /boot partition.

Now from my understanding no where is there a modprobe or ismod for ext3, when the mount command is run to mount the root parition, mount or the kernel know that hey this is a ext3 parition, lets load that module.

So they is why some people make the /boot partition ext2 because kernels from Gentoo (maybe) and RH or CentOS use module based kernels and the file system modules is kept in the initrd image on the boot parition.

Michael

Are we talking about a few kilobytes of space and a few milliseconds of time ? I'm sorry, but i don't see how anyone should care even if its half a meg space saved, when nowadays people have gigs worth of space to spare.. Its like saying you prune your logs and delete temp internet files every hour to save on space...

Bluesuperman,
That's actually a very good argument there. I had the exact same problem on an old machine and didn't have a clue to what the cause was after compiling 2.6.11 on it. So i guess its more to do with failsafe reasons than speed/performance increase reasons for ext2 on /boot.

even if you make the /boot partition with reiserfs, and there's no reiserfs support in the kernel,
or in an initrd, the system will boot fine.
the kernel doesn't give a hoot about the filesystem on a separate /boot partition.
it needs fs support to mount the *root* partition.
it's lilo that reads the kernel into memory, and it uses no filesystem but sectornumbers to locate what it needs.

----from the lilo-doc----
* LILO does not know how to read a file system. Instead, the map
installer asks the kernel for the physical location of files (e.g. the
kernel image(s)) and records that information. This allows LILO to work
with most file systems that are supported by Linux.
------------------------

so there's no reason to choose any of the possible filesystems.
they are all ok, and don't need kernel support.

egag