Since most RAID servers can't even flood a 100 mbit connection, you're more
than safe with that much bandwidth if most of your traffic is going to be
database related. You might want to factor in all the other network
traffic that will be going over those lines though. For instance, if the
app servers are going to be mounting partitions off of a RAID server on the
same network, and your Internet connection comes in there too, you might
start to run into problems. The database shouldn't even come close though.
At 06:49 PM 6/30/00, you wrote:
> OK, I feel silly having to ask this, but I'm paranoid enough that I will
>anyway.
>
> The company I work for is about to plop down a very large amount of money
>on bigger, better machines to handle the work. We're currently planning on
>an 8-way machine running postgres for the database work, and a group
>of dual CPU web servers running the CGI applications.
>
> Before we get up to our necks in hardware purchases, I'd like to have
>some peace of mind that the performance isn't going to decrease horribly
>because of the bandwidth limitations in the ethernet connections.
>
> To describe the setup, the database server will be connected via a
>gigabit fiber cable to a switch, with 100-megabit connections to each of the
>application servers. So, until we get a larger number of app servers, the
>limiting factor will be the 100 megabit connections to each individual
>server.
>
> I'd like to feel sure that transmitting the result sets over the ethernet
>isn't going to cause a significant decrease in response time. After working
>through the numbers, I don't think that it will - but I'd love to hear from
>those who have done similar setups.
>
> We enabled some logging in the database library that we use, and here is
>some information on our result sets:
>
>average result set size: 1.4 kilobytes
>maximum result set size: 633 kilobytes
>
> Of those results, here's a breakdown:
>
>Size Frequency
>-------------------
>0-8K 96%
>8K-17K 2%
>17K - 24K 0.02%
>
>and it goes down from there.
>
> So, it seems that it would take a very large number of transactions per
>second to saturate either the 100 mbit link to the servers, or the gigabit
>pipe to the server.
>
> Am I correct, or should I reevaluate? Any comments are welcome.
>
>steve
