Brad Lackey - US-SW Desktop Product Lead wrote:
The issue is that if you set up a FOG across the WAN, you will be
subject to the load balancing mechanism deciding where your sessions
will live.
For example... We have two sites Site A and Site B These sites have
100MB local LAN's but are connected by a 4MB WAN link. There is one Sun
Ray server at each location, and 10 DTUs at each location.
If you set up the servers at both sites in a FOG, DTUs from each site
may have sessions on the other site during normal operation. This
wouldn't be the best use of your WAN link bandwidth.
What most customers want is their DTUS to connect to a local Sun Ray
server, and if in the case that server is down, connect across the WAN
to the alternate.
There is no Need to put these in a FOG to do this. The two things that a
FOG does is Replication of policy/registrations and load balancing.
Your best bet is to use your configuration mechanisms to give the DTUs
BOTH servers as connection targets in the preferred order.
For example, put both your servers in the servers= line of your .parms
file and set select=inorder. The servers= lines will be opposite on both
of your servers.
There is one issue with such configurations. When
the local servers go down you'll connect across
the WAN and create a new session. Super.
However, after the local servers come back up,
you'll no longer connect (automatically) to your
WAN-remote session which was in use during the
outage. So, you won't easily be able to save the
work or exit the session applications gracefully.
The only way around this is to use
/opt/SUNWut/bin/utswitch -r -h wanhost (where
'wanhost' is some host in the remote FoG) which
should locate your session in the remote FoG and
connect to it. You'd then save your work, exit
your session, and power-cycle your DTU to connect
back to the local FoG. This is a bit painful
but beats not being able to work during an outage.
This is assuming a 2-tier deployment where you are
running your apps directly on the SR servers. If
you have a 3-tier deployment (e.g. to Windows
servers at a back-end) your issues and recovery
requirements may vary depending on what you can or
can't access during the outage.
-Bob
Disclaimer: Opinions expressed in this mail are my own,
and are not necessarily shared by my employer
_______________________________________________
SunRay-Users mailing list
[email protected]
http://www.filibeto.org/mailman/listinfo/sunray-users
