VMware vSphere

I have about 80-90% memory usage on a constant basis. Is there any concern for this amount or do I need to add more ram? I have 48 gigs and while I have about 12 VMs on this server none are heavy duty except maybe one SQL server.

thanks

Gary

The first question that pops in my head is are you overcommitting memory?  If so, then I would recommend adding more RAM because you might push yourself into a situation of contention.  If you load is not great and your other VMs are not using a lot of memory or are not memory intensive then you may be ok.  I normally try to keep my hosts at 70-75% usage but again this is dependent on your needs.

depends on your virtual environment.

If you are using HA, and all of your hosts are 90% then you are going to have issues if you lose a host.

Other than getting constant alarms (which you can change) your only real concern is adding more vm's...

low

you may think about upgrading the amount of RAM on your ESXi Host, or look at getting another to spread the load.  However, if the enviorment is functional and you are considering this ESXi as closed (no more guests), then you may be ok.  But, RAM is cheap, I would go for more RAM.

Troy makes a good point...RAM is cheap and more RAM never hurt anyone!  :smileyhappy:

This is a Del R710 and from what I understand when I go the next level of ram it slows down the speed of the ram. They have to be installed in particular sets. I do not get any alarms. Does the memory usage come from how much ram I have commited to each vm's as I have some I can back down or is it real time and because of the committment levels is going to use it anyways.

When I bought this before to go from I think 12 to 48 I had to ditch the 12 and the 48 cost me about $2500.

Does the memory usage come from how much ram I have commited to each  vm's as I have some I can back down or is it real time and because of  the committment levels is going to use it anyways.

Yes and no. Most of the usage comes from active memory used by  your guests.  You may also want to ensure you have no  limits set on any  of your guests.

I would look closely at how much RAM you have allocated to each VM. If it isn't necessary you could certainly back off the allocation.

RAM is cheaper, not cheap, imho.

The problem with server RAM upgades is you are usually replacing entire banks of memory, not just adding a couple of sticks.

and the price increase for the larger sets of memory is huge.

That said, I agree, memory=GOOD.

low

I just emailed my memory vendor and I haven't touched the 2nd bank yet so I hope I don't have to ditz the first bank which is filled. I will post what I find.

Gary

Is this host in a cluster?  Remember, HA should be in your calculation as well.  What happens if this host fails?  How much load will you push to other machines?

-KjB

This is a standalone. We will be implementing a cluster but not until next fall when we get the NAS etc. 

I actually have 2 slq servers on this server so I checked with the vendor this morning on the main application that I use for sql and they said it could handle the other databases just fine. The one that I will be ditzing had 16 gigs of ram committed to it and the other one 12 so that will free up a lot of memory once I do that.

The memory vendor said I can do the 48 gigs for about $1300 so not a bad deal on that. He sent me a link to a Dell page on optimizing the memory so I don't have a slowdown. More memory will be the ticket.

thanks

Gary

In esx 4.x you should'nt be concerned as it is likely that most virtual machines use a hardware MMU, thus using large pages to back virtual memory to physical memory. Large Pages are excluded to be collapsed and shared by TPS until 94% of available memory is used.

Once ESX detects less than 6% free memory it will break the large pages use the pre-hased memory blocks and randomly pick 4kb memory pages to be shared by tps.

This is common vSphere behaviour.

Thanks, I would have never known that on my own.

Hi,

Best is to follow the top 25 bloggers. http://vlp.vsphere-land.com/

Content about this kind of behavoir can be found on http://www.yellow-bricks.com and my blog http://frankdenneman.nl.

Thanks for awarding me the points.

Frank