phil@softway.sw.oz.au (Phil McCrea) (01/18/91)
Softway has developed a kernel based resource management product called
SHARE II, and will be demonstrating it on SVR4 on the Unix International booth
at Uniforum in Dallas next week. If you are planning to attend, we'd like
to give you a demonstration.
Marketing style info follows.
Do not proceed past this point if advertising offends ...
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SHARE II
RESOURCE MANAGEMENT FOR UNIX
Softway can provide badly needed resource control for UNIX systems in
the form of SHARE II. This is a kernel level product which keeps
track of the resources of a machine, and allows resource limits to be
placed on users and groups. The resources include:
o CPU (using the Fair Share scheduler)
o disk space
o system memory space (real or virtual)
o process count
o printer pages
o system privileges
o terminal connect time
o customised, site specific resources
DECENTRALISED ADMINISTRATION
Assigning resource allocations and dealing with users' requests for
changes is a heavy burden for a single, central administrator. Under
SHARE II, the central administrator can grant control of a group's
internal resource allocation to a nominated sub-administrator of that
group. SHARE II allows hierarchical groups to be defined, and sub-
administrators may grant similar control to sub-administrators of
groups within their own. In this fashion, responsibility for user
resource allocations can be properly delegated and sub-delegated to
appropriate individuals, thereby reducing the problems of user
administration to easily manageable levels.
FAIR SHARE CPU SCHEDULER
The Fair Share scheduler is the result of 8 years of development at
the University of Sydney, and is currently part of the operating
system offering from Cray Research and Convex. The scheduler
guarantees that each user and group will receive their long-term
entitlement of the CPU.
The Fair Share scheduler works as follows:
o Each user and group is allocated shares in the CPU (analogous to
shares in a corporation);
o It records the history of CPU usage of each user and group over a
recent period (which is tunable);
o It dynamically alters the priority of each user's and group's
processes to force their relative usages to conform to their
relative shares.
The benefits of the Fair Share scheduler are:
o Users always receive their CPU entitlement in the long run,
regardless of the actions of other users. They therefore tend to
consider themselves responsible if they experience poor machine
response, because the poor response will have been caused by
their own recent heavy usage. This encourages users to use the
machine intelligently.
o Users may be encouraged to take advantage of times during the day
or night when CPU time is charged at a more favourable rate,
thereby spreading machine load away from peak times.
o The common trick of hogging the CPU by running many concurrent
processes no longer works. In fact, users are rewarded for
reducing the priority (increasing the nice ) of their processes.
The term "nice" now implies that users are being nice to
themselves as well as to others!
The benefits of SHARE II Resource Management are:
o Users with differing requirements (e.g. word processing and
chemical analysis) can be allocated resources appropriate to
their needs.
o The hierarchical hard and soft disk domain limits provide far
greater flexibility than existing disk quota systems.
o SHARE II is hierarchical - it permits a machine's resources to be
divided along the lines of an organization's structure. Two
divisions who share a machine may be allocated (say) 50% of the
online disk storage each; each division is then able to allocate
its disk how it pleases amongst its departments; each department
may allocate its own disk amongst groups and so forth, down to
individual users. The same applies for memory, number of
processes, CPU time, printer pages etc.
o SHARE II may be used to control the amount of CPU time and disk
space that system software such as network daemons consume, to
prevent nodes from being swamped by network traffic.
o SHARE II eases the administrative load on the overall system
manager. The head of a secretarial section, for example, may add
a new user without needing root privilege, and without disturbing
the system manager.
o The ability to delegate routine, user-related system
administrative privileges without granting root permission
means that system security is significantly enhanced.
o SHARE II has been designed with flexibility in mind: it may be
customised to manage resources that are peculiar to any
particular architecture or application.
o SHARE II accurately records the accumulated usage of all
resources, making it possible to prepare detailed reports on
resource consumption, and to issue invoices where appropriate.
--
Phil McCrea - Softway Pty Ltd (phil@softway.sw.oz.au)
PHONE: +61-2-698-232 ADDRESS: 79 Myrtle Street
FAX: +61-2-699-9174 Chippendale NSW 2008, AUSTRALIA