init observations

[Chris Adams]

Once upon a time, Bill Nottingham <notting at redhat.com> said:
> OK, this is something I've been meaning to ask about - who
> still uses network /usr, and why do you use that instead of
> network /  ?

I don't currently use network /usr, but I typically have /usr on a
separate fs from / (at least on servers).  I then can mount /usr
read-only which means:

- no writes - less chance of an "oops" (either due to kernel fs error or
  user admin error)
- in the case someone does break into the system somehow, less chance of
  them doing anything meaningful (since they'd have to know to remount
  /usr read-write)
- / is smaller - less to go wrong/get screwed up that would keep the
  system from at least booting in emergency mode

Network / would only be useful between identical systems using DHCP,
since /etc contains users/passwords, network config, hardware config,
etc., unless you want to make /etc a separate fs (which has the same
problems as trying to mount /usr from initrd).

Other problems with /usr being mounted from initrd are handling fsck,
/usr on different device from / that requires additional init, etc.
Look at what happens in rc.sysinit before other filesystems are mounted.

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.