>>>>> "mg" == Mike Gerdts <mger...@gmail.com> writes:
mg> If Solaris is under memory pressure, [...]
mg> The best thing to do with processes that can be swapped out
mg> forever is to not run them.
Many programs allocate memory they never use. Linux allows
overcommitting by default (but disableable), but Solaris doesn't and
can't, so on a Solaris system without swap those allocations turn into
physical RAM that can never be used. At the time the never-to-be-used
pages are allocated, ARC must be dumped to make room for them. With
swap, pages that are allocated but never written can be backed by
swap, and the ARC doesn't need to be dumped until the pages are
actually written.
Note that, in this hypothetical story, swap is never written at all,
but it still has to be there.
If you run a java vm on your ``storage server'', then you might care
about this.
I think the no-swap dogma is very soothing and yet very obviously
wrong. If you want to get into the overcommit game, fine. If you
want to play a game where you will overcommit up to the size of the
ARC, well, ``meh'', but fine. Until then, though, swap makes sense.
pgpA7wEb34DwB.pgp
Description: PGP signature
_______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
