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Re: /usr/lib vs /usr/libexec

Russell Coker <russell@coker.com.au> writes:

> On Tuesday 10 May 2005 10:36, Goswin von Brederlow 
> <brederlo@informatik.uni-tuebingen.de> wrote:
>> - / can't be on lvm, raid0, raid5, reiserfs, xfs without causing
>> problems for /boot.
> I believe that there are LILO patches for /boot on LVM.  There's no reason why 
> GRUB and other boot loaders couldn't be updated in the same manner.  The most 

They don't now and there are way more bootloaders than just grub and

> But generally the best solution to such problems is to have a separate 
> partition for /boot.  Red Hat defaults to an LVM install (including LVM root) 
> with a regular 100M partition for /boot, that works well.

No lvm backup data available in case of superblock corruption. Bad
idea. No booting with init=/bin/sh to patch things back together as /
can't be mounted. Bad idea again.

/ on lvm is a major pain in case of error and if you already need a
seperate / partition adding another for /boot is a bit stupid.

The best solution is a regular 100-200Mb partition for / including
/boot imho.

>> - a larger FS has more chance of failing so you risk having a fully
>> broken system more often
> I doubt that.
> I think that a FS that is written less has less chance of failing, which is an 
> extra reason for having /var and /home on different file systems to /.  If 
> you have /var and /home on separate partitions then / should not get many 
> writes and should have little chance of corruption regardless of size.
>> - /usr can be easily network (shared accross the same arch) mounted
>> while / (due to /etc) can't
> Why is this desirable in the days of large disks?  There is no machine for 
> which I am responsible which has a disk space issue other than my laptop.  
> None of my machines has /usr taking any significant portion of the disk 
> space.

I have two recently bought systems without disk. Just a small flash to
boot from. Those mips based wireless and dsl routers from linksys and
similar are very popular as well as meshcubes.

>> - / needs functioning device nodes on it while usr can be mounted nodev
> The current Fedora setup of having an initrd create device nodes on a tmpfs is 
> working quite well and could be copied for Debian.
>> - a small / can be replicated across many disks to ensure the system
>> always comes up and e.g. at least send an email to the admin. / can
>> even be an initrd
> How big can an initrd be?  The default is 4M which isn't going to do well 
> for /.

The limit is either 1GB or slightly below 2GB for 32bit (+amd64)
systems. Less for mips I guess due to the hardwired address space.

Enough ram provided of course (4GB ram for a 2GB ramdisk as it gets
copied around by the kernel).

The problem is more how much ram do you want to spend on it than how
much linux can use.


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