Applying SUM twice in the same query.

I have a table structured:

server_name        |server_version  |number
-------------------+----------------+------
Apache             |1.3.11          |     1
Netscape-Enterprise|2.01            |     1
Apache             |1.1.3           |     2

Initially I wanted to extract the total count by server_name; this is pretty
straightforward:

select server_name, sum(number) 
from web_servers 
group by server_name;

...gives the result I expect.

server_name        |sum
-------------------+---
Apache             | 64
Draupnir           |  1

I also want the total number of of servers.  This can be obtained with:

select sum(number) 
from web_servers;

Again, works fine.  What I really want to do with total is to derive a
proportion of number of server:number of servers, something like:

server_name        |number|total
-------------------+------+-----
AiNET Apache       |     1|   84
Apache             |    64|   84
Draupnir           |     1|   84

The problem is, I can't forumlate a query to produce it.  The closest I got
was:

SELECT ws1.server_name, SUM(ws1.number) AS number, SUM(ws2.number) AS total
FROM web_servers AS ws1, web_servers AS ws2 
GROUP BY ws1.server_name;

...which is producing:

server_name        |number|total
-------------------+------+-----
AiNET Apache       |    19|   84
Apache             |  1216|  840
Draupnir           |    19|   84

I assume I'm creating a product of the query, but I'm not sure how to fix it.

-- 
Rodger Donaldson        rodgerd@diaspora.gen.nz
Driving that fast may also be an autoLART because the acceleration required
to reach a high fraction of c in just a few kilometres may be difficult to
withstand.  You will also need a better fuel than gasoline.     -- Steve VanDevender