-----Original Message-----
From: Matevz Tadel
Sent: Thursday, March 20, 2014 12:36 PM
We're setting up RR-DNS for US-CMS now ... and I still don't understand what
any/all do when subscribing a manager to a set of meta-managers.
all.manager meta all cmsxrootd.fnal.gov+ 1213
I thought that namespace cache on (meta) managers is only populated with
things
that they actively query. Are managers actually pushing their caches upwards
to
meta-managers? But then neither any nor all is any good as the caches will
still
end up on one meta-manager only and client connections come in from a random
one.
I thought this kicks in for client requests that can not be served locally
and
have to be redirected upwards.
Please explain! :)
----------------------------
Hi Matevz,
Sure. The basic problem is that you are confusing xrootd with cmsd. The
cmsd is what is caching the information and only xrootd's connect on a
client's behalf. So access is strictly controlled and is deterministic. When
you specify "all" the requests are load balanced in such a way that the
cache is not duplicated across cmsd's unless one of them dies. For "any"
(which makes sense if there are only 2 cmsd's) always uses a particular cmsd
unless it dies. So, again, caches are not duplicated across cmsd's.
Andy
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