Summary: Do you run Unix without disk quotas?

[Tim Cook]

My promised summary of responses to my survey on Unix without disk quotas:

>  1.	Have you implemented any other method of controlling disk usage?
> 	If so, what does it entail?

Most of those who had, had a set of shell scripts that regularly checked
for the greatest over-users of disk space, then hassled these users (or
left the hassling to the administrator) to get them to clean up.

>  1a.	How difficult was the implentation of this alternative?

For those who had a homebrew shell-script alternative, the implementation
was usually easy.  A few mentioned that they had got their system from
somewhere else, indicating that there is some (semi?) serious development
being put into this area.

>  1b.	Is it effective?  Is it better or worse for the administrator
> 	and for the user?

The homebrew systems were more or less effective.  They could not prevent a
partition from filling up, but most users would respond to any hassling
they attracted.  Of course, some users (notably, those who are on holiday
or otherwise unavailable) can be difficult to budge.

>  2.	If you have not implemented an alternative, how much more disk
> 	space do you think you use (if any)?

Some alternatives put all users in one group onto a common filesystem, with
resposiblity for disk usage passed over to someone with some authority in
that group. For most this means you need a large number of medium-sized
filesystems, preferably of adjustable size, and it still has the same
shortcomings of the shell-script-hassle system for the individual groups.
Almost all respondents were sure that they were using more disk space.
Some noted that disk space is relatively cheap, though.

>  3.	How much more time does the system administrator spend controlling
> 	disk space usage, either with an alternative method of control, or
> 	"by hand".

For some, a very small amount of time.  For others a lot.  For all, it
meant constant (at least daily) attention.

>  4.	How would you rate the presence of a disk quota system in
> 	importance, compared to other system features (for example, dynamic
> 	disk bad-block re-mapping, an extended access-control mechanism,
> 	or adherence to contemporary Unix and Open Systems standards).

I got a very mixed response here.  Generally, those who had an alternative
that worked well did not see disk quotas as important.  Those who were
feeling the humdrum of monitoring students who have fits of FTP-ing GIF's
and other assorted goodies were a bit cynical about the other things I
listed.

In summary, I am convinced that a hard quota system would be the most
desired ``option'' on a Unix system used by a large number of users.  Some
mentioned that a hard quota system would not allow a user access to a large
chunk of disk on a ``temporary'' basis, such as would be needed to compile
a large system, or perhaps for manipulating a large dataset.  I would
answer this by saying ``They can ring up and ask'', or ``What about /tmp or
/usr/tmp?''.

The one thing I have learnt from being a Systems Administrator is
``automate or delegate''.  All of the alternative systems were not and
could not be fully automated.

I would like to thank all those who responded.  I received about two dozen
responses, including one from Elizabeth Zwicky of SRI International, who
gave me a copy of a paper entitled ``Disk Space Management Without Quotas''
that she presented to the Third Annual USENIX Workshop on Large
Installation Systems Administration.

The file pub/non-source/quotas.Z, a compressed copy of my mail folder
containing these messages (including this summary), will be available from
the anonymous-FTP area on admin.viccol.edu.au by the time you read this. 
If this doesn't suit you, I can mail it.
--
Tim Cook	Systems Administrator, Victoria College Computer Services