[386] in Moira
resource control within moira
daemon@ATHENA.MIT.EDU (Mark Rosenstein)
Tue May 5 23:15:05 1992
Date: Tue, 5 May 92 23:14:31 -0400
From: Mark Rosenstein <mar@MIT.EDU>
To: moiradev@MIT.EDU, dbadmin@MIT.EDU
I've been thinking about the "Islands of Control" issues for moira,
and have some ideas along a similar line to what NCSU did. Below is
some brainstorming on that. Before any of this goes too far, we have
to examine just what IS's needs are. However an idea of what is
possible can influence the requirements.
I'd like to create an object for the database called a resource
authority or something like that. RA's can own and grant resources.
A resource might be "quota" and a number of disk blocks, or "server"
and the name of a fileserver, etc. Each resource has pointers to the
owning RA and the granting RA. What's the difference between the two?
The "ops" RA might grant 5 Gig of disk quota to the "f_l" RA, which
now owns it and may in turn grant some of that to the "6.170" RA which
may then grant some of that to each of 15 lockers. When an RA grants
some of its resources to someone, a record is kept of how much of that
resource it still holds. When some resource is deallocated (a quota
reduced, for example), the granting RA regains that resource.
RA's have a name, an ACL, and an MIT account account number. The
account number may be used for billing for some resources at some
point in the future. It may be useful for printers right now. The
ACL says who can manipulate these resources. But should RA's be new
objects within the database, or additions to the current list
structure (i.e. an RA is a list with the is_ra flag set, and maybe an
account number filled in)?
Each RA is associated with a list of resources. A resource record
contains type, a total value, a retained value, an owner, and a
grantor. As a resource is granted away, the retained value shows how
much of the total value is still under the owner's control.
A change to an existing database structure is that disk quotas would
become resources. All existing quotas would be granted by SYSTEM
until we sort things out. Eventually, users would have their default
quota granted by SYSTEM, but additional quota to work on a thesis
would be granted by their department so we could keep track of usage
better. This means when someone buys their own disk (i.e. ACS gets 5
Gig of disk) we could grant them that quota to allocate as they wish.
Does it mean that a student who doesn't use all of his default quota
can grant some of it to a classmate who needs more quota?
Also, when someone owns a departmental NFS fileserver, they can
actually be granted the right to create lockers on it.
-Mark
