load balancing question
John E. Malmberg
wb8tyw at qsl.net
Wed Oct 9 11:34:00 GMT 2002
To clear up some confustion in this thread.
A DFS will only help distribute the load if the clients are accessing
files in different directories.
\\host\share\dir1\ would be served by host_1
\\host\share\dir2\ would be served by host_2
\\host\share\dir3\ would be served by host_3
If all the clients are reading the same file say in \host\share\dir1\
then using the DFS does not help at all. All the requests will be
handled by host_1.
If you have a fail-over disk system that is common to the three hosts,
then dir1, dir2, dir3 can be moved from one host to another as needed,
but the move is time consuming, and still one host at a time.
In a shared access disk system such as in an OpenVMS cluster, you have
\\host\share\dir1\ would be served by host_1, host_2, and host_3, ...
\\host\share\dir2\ would be served by host_1, host_2, and host_3, ...
\\host\share\dir3\ would be served by host_1, host_2, and host_3, ...
With an I.P. alias, clients can be connected to any host and still have
access. This will load share.
And DFS has no involvement in the scheme, and provides no advantage.
DFS only helps if the clients are reading files out of different
directories, which is not how I am interpreting the information in the
post that started this thread.
DFS can be enhanced to allow a better fail over mechanism for the
platforms that do not support simultaneous access to a common disk. But
that is not load balancing. All clients accessing the same directory
are either all on the same host, or one host will have direct access,
and the rest will be taking a second indirect path through the network.
Locking is an issue. Samba 2.0.6 for OpenVMS uses file system locking,
and the slower share locking. I am not sure about the 2.2.4 port.
wb8tyw at qsl.network
Personal Opinion Only
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