So I'm running Plesk 7.0.2 running on my server and it's using 700MB+ of memory. Is this normal? The number seems rather high, and I'm wondering if there is some way to reduce the amount of memory Plesk is using. Is there any way to that? Is Plesk working right?

Which system are you using ? Windows, Linux or FreeBSD ?

Linux Redhat Enterprise and ... CPU is 2.4 Celeron.

I'd say that is normal from my experiences. Most of it is probobly in cache which is just the allocated memory used by processes. Not all of that cached memoery is actually being used, just allocated for a process if needed. After running for about 20 days, my server gets about 20-40MB free RAM and uses about 200-300MB swap. It all runs pretty smoothly as it is all just web. If running games and stuff of that sort on the server, than I would suggest another GB of RAM.

That depends... 700mb is not normal for a server with 1 site serving 2 visitors a day. It's not normal for 2000 sites servring 10 mil php pages a day. You will have to be more specific in your question. What kind of pages do you serve? How many websites? How many visitors?

I saw this number just when I got the server, meaning that there was no web site hosted. Consequently, no visitor except for me, of course. I was the only one accessing the server and I was using Plesk. That's it. Now ... what are the possible causes?

Could you paste the entire lot of information about the memory so as to prevent any misunderstanding ?

How can I do that? (sorry, beginner question)

Where did you see the memory usage going up to 700mb then just copy and paste that information with the exact wording.

The following is from Plesk -> Server -> System statistics

Memory Usage

Total 1.46 GB
Used 750.85 MB
Free 744.75 MB
Shared 0 B
Buffer 66.73 MB
Cached 507.86 MB
Usage 50.2%

Here is what I figured :-

Used (750.85mb) + Free (744.75mb) = 1.46gb

The memory used would include the cached of 507.86mb so the effective memory usage is 750.85 - 507.86 - 66.73mb = 176.26mb, the rest is just cached memory.

Linux is known to just allocate memory for specific purposes even if they are not being used. The memory method is very different from Windows which only allocated when used.

So if I am not wrong, you are pretty much in safe hands. If you add more memory, more would be allocated.

A couple of things I plan to do include the use of Tomcat and allowing MySQL to use more memory. How do they affect this? Does the memory usage(including cached memory) go up? Does the memory usage stay around the same while cached memory decreases?

You still have 744.75mb at the moment which is not allocated for anything. What is important is to check to see that the Swap memory usage goes up too much. I don't remember the command to show the swap memory usage now.

Probably if you have tomcat, there would be more memory usage but I am not sure by how much.

Well, I can check this from Plesk as well. Now how much is too much? BTW, my swap memory is set to 2GB and it's barely used currently.

Well, if your swap is barely used then that means you have tons of free memory to use. Basically, here's the deal. Swap memory is the allocated harddisk space to use as memory when your physical memory runs out. So if your swap is not used or barely used then you have a lot of free road to go.

We have a RHE server that shows usage of 980mb of 1GB memory with actual usage appearing to be around 512mb. This is basically a baseline with little activity on the server, but the server is running Tomcat along with mysql, postgresql, etc.. so it should give you an idea how much more Tomcat might require than a server without it.