I have set up my first ESX Server and was hoping some one might help me out with a question about memory usage
The config of my ESX Server is a follows :
2 x Dual Core 2.8 Ghz Processor with 8 GB of RAM, i have set up the following VM machines on the ESX Host
dr-esales - SQL Server, Windows Server 2003 3 GB RAM
dr-www - Webfront end , Windows Server 2003 3GB RAM
dr-webshpere - apps, windwos server 2003 3 GB RAM
When ever i power these machines on then i get all sorts of memory usage alerts, for hosts and vm machines. this seems to sort itself out once all machines have booted. However the host still runs with a memory usage alert.
Have i configured my systems correctly or is there a better way to configure the memory set up.
With ram (3X3GB) you have overloaded your esx host (RAM only 8 GB). I'm not sure if your vms need so much memory - you can configure it lower at first and see what happens by working.
One thing you should know about ESX, if ALL VM's are the same OS architecture, VM Ware can actually share the CORE, and memory requirements are 30% less right off the top. So that should reduce your RAM from 3 to 2.
The next thing is, since the drivers from the VM Tools are generic, you don't have to worry about vendor based driver support, plug and play, and they don't have to work as hard to manage the hardware. The overhead for each VM is less, and I would say (in my experience) is another Gig.
So you are now at 3Gig TOTAL for all your VM's (1 gig each). I would speculate that you really don't need that much RAM. I fight with developers all day long about memory. I will bet any amount of money, there isn't a single Windows Machine with conventional software that \*NEEDS* more than 2 gig of RAM.
I have yet to see it, or have proof of such an animal. I see wasted memory, uncessary running programs, running multiple programs side by side that shouldn't, programs that take the RAM, reserve it, but ACTUAL usage, just isn't there. So I would reduce each one of these VM's to a moderate level, like 1Gig, and check the performance tab in Task Manager, you might be surprise you have way more memory than you will actually use.
SQL, does have high memory requirements, but you can reduce the other 2 VM's with no problem, maybe leave SQL at 2G, but try it at one to see what happens.
Thanks for the information I shall try as you have suggested.
If i set the three VM's to 1GB Memory, that means I would have 5GB of un-used memory. Does that mean that if a one of my VMmachines started using a lot of memory and it reach the 1GB allocated limit, would it then start using some of the unallocted 5GB memory or would this go un-used.
Just another quick thing, i have set all the VM's to 1GB Memory but on boot up they all come up with Virtual Machine Memory warnings red and then amber - is this suggesting they need more memory ?
I see the same thing on VM's when I boot them. Memory and/or CPU alerts.
I think the the alerts are triggered when the memory or cpu usage goes up, but then the alert doesn't go away after the cpu and memory usage drops. I think that it doesn't go away for a minute or so. I believe that the alert/warning it isn't a real-time indicator.
Message was edited by:
See this thread for the answer...