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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.micro.att,net.unix-wizards
Subject: Re: instability in Berkeley versus AT&T releases (absurdly long)
Message-ID: <5838@utzoo.UUCP>
Date: Mon, 29-Jul-85 16:46:26 EDT
Article-I.D.: utzoo.5838
Posted: Mon Jul 29 16:46:26 1985
Date-Received: Mon, 29-Jul-85 16:46:26 EDT
References: <2067@ucf-cs.UUCP> <363@cuae2.UUCP> <2423@sun.uucp> <5819@utzoo.UUCP>, <2494@sun.uucp>
Organization: U of Toronto Zoology
Lines: 35

> Which means, if the utility is important enough that it's worth the work,
> the best strategy might be to "diff" the suckers and take the best from both
> and put it into one version.

Also important is to take the worst from both and *not* put it into the
new version.

> > The lack of file system quotas probably reflects AT&T's openly-expressed
> > view (which I agree with) that except in special situations, if you think
> > you need disk quotas then you really need more disks instead.
> 
> ...Think of it as an economic
> problem; you have a scarce resource, but the price mechanism has a long
> time-scale over which it works - possibly too long to prevent short-term
> space shortages.  Quotas can keep users from eating the disks until you can
> buy new ones...

The AT&T observation was not that there is no reason for quotas, but that
(like password aging) they don't work satisfactorily.  If you can *impose*
quotas on your user community, you can make them work.  If users can argue
with the quotas, then you're sunk, because the sum total of the quotas that
users feel they can live with probably exceeds the size of the disk.  That
is, if disk space is short enough that you *need* quotas, it's probably
overcommitted already.  My own experience with space-short systems certainly
supports this claim.  There is also the related problem of maxima becoming
minima:  "I'm under my quota, so I don't need to clean up yet".

I have no personal experience with quota systems, but I really wonder if
they aren't like password aging:  a superficially-plausible idea that
doesn't really work all that well.

Hostile users are another story, of course.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry