Shareable, networked, swap device?

[Larry McVoy]

In article <AGLEW.90Oct25235828 at cobra.crhc.uiuc.edu> aglew at crhc.uiuc.edu (Andy Glew) writes:
>Does anyone have a shareable, networked, swap device?
>
>    In any typical network of n machines, each machine is allocated,
>say, 32M of swap space, for a total of 32*n megabytes.  But, in our
>network, typically half of the machines are not being used at any time,
>so they typically have around 30M of swap-space free.  At the same
>time, a much smaller fraction of our machines are running very large
>jobs, and really need swapspace around 64-128M - but these aren't
>always the same machines (not designated compute servers).  
>    It really would be nice if the unused swap memory of some machines
>could be used to temporarily, transparently, expand the swap memory of
>others, on demand.  Ie. it would be nice if swap space was a
>centralized resource pool, rather than fragmented.

Do you want any fairness?  Should hostA be able to use up all the swapspace
to the exclusion of b, c, d, and e?  Should the OS provide hooks to allow
you to tune this?  How would you tune it?  What hooks do you want?
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Larry McVoy, Sun Microsystems     (415) 336-7627       ...!sun!lm or lm at sun.com