Survey
Richard M. Mathews
richard at locus.com
Tue Sep 11 11:41:08 AEST 1990
fwp1 at CC.MsState.Edu (Frank Peters) writes:
>Well, we are developing a different kind of 'large system' that has
>its own unique complexities.
Good point -- large networks are also supposed to be part of this
newsgroup. Actually, we have both kinds of "large" systems. As I
said before, we have many AIX guests running on our 3090. We also have
a handful of other 370s, each with a number of AIX guests. Finally we
have many PS/2s running AIX. Groups of these are connected via TCF,
and we use good old fashioned telnet, rlogin, NFS, etc. to connect the
clusters.
>(3) Load balancing. In a single box balancing the load among several
> CPUs is relatively straitforward (at least in concept). When
> your CPUs are spread across a dozen or more machines how do you
> avoid the situation of one machine being sunk to its knees while
> another is nearly idle. When you add multiple classes of
> processor (is a 4/490 at 50% more loaded than a sparstation at
> 30%?) or multiple types (how do the above two compare to a
> decstation 3100 at 40%?) this issue can become a nightmare.
TCF allows processes to migrate between machines, and I know there are
others developing similar capabilities. I can send a signal to a process
to request that it move to a new site (by default, to the site from which
the signal was sent). A load leveling daemon could be written (but one
does not come with TCF) which automatically moves processes around in
response to varying load. A difficulty is deciding which processes to
move -- it would be a shame to waste time moving an I/O bound process
which is currently accessing local data. In our environment I have
found it quite sufficient to be able to manually move things when the
load goes up.
Richard M. Mathews
Locus Computing Corporation
richard at locus.com
lcc!richard at seas.ucla.edu
...!{uunet|ucla-se|turnkey}!lcc!richard
More information about the Comp.unix.large
mailing list