guru input needed! (re-inventing disk quotas)

[Net Llama!]

THis sounds like it would work, except, what happens if someone wants to
pay for 20MB of space?  Sure, you could create a loop back file of 20MB,
but this doesn't seem all that elegant.

Also, copying the contents of one 'allocation' to a larger one is also not
all that elegant.

On Mon, 8 Apr 2002, Douglas J Hunley wrote:
> Morning all:
> 	I have a client that wants to migrate to Linux from Solaris, but one of their
> main "gotchas" is the quota support in Linux. They believe (as do I) that
> quotas seem to be the first thing broken (and the last thing fixed) whever a
> change is introduced into the fs or block layers of the kernel. They
> currently have a *very* detailed accounting system in place that charges
> their internal customers (departments) based on disk usage, CPU usage,
> network utilization, etc. They don't want to lose any of this when they go to
> Linux. I believe I have solutions for everything but the disk quotas.
> However, I have what I think is a neat idea for solving the disk issue. I
> would like opinions.
> 	What I propose is this:
> 1. create /loops on the main disk server
> 2. for each user on the system, use 'dd' to preallocate a file in /loops:
> 	dd if=/dev/zero of=/loops/joe bs=1k count=10240
>    which would create a 10M (if my math is right) file called /loops/joe
> 3. chown joe:users /loops/joe
> 4. configure the automounter to mount the newly allocated file as joe's $HOME
> 	mount -o loop /loops/joe /home/joe
>
> Obviously, I would have to create a local 'create user' script to allocate the
> file, and add the entry into the automounter config.
>
> The biggest caveat I can see is that "joe" would be charged for 10M even if he
> only used 2M. I already ran this concerns by them, and they seemed OK with
> it. They said they would be happy selling disk in chunks like this. And we
> could always "extend" the allocation be creating a joe2 of the new size, and
> then copying the contents over and moving joe2 over top of joe.
>
> This will free them from worrying about whether or not the current quota code
> is working properly, and would easily enforce the hard limit. (there's no way
> that joe could write 11M of stuff. he'd get ENOSPACE).
>
> Thoughts?
>

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lonni J Friedman				netllama at linux-sxs.org
Linux Step-by-step			     http://netllama.ipfox.com