Number of VM's per Host

[curiousagain]

Hi,

I have a very powerful HP server with 64 GB RAM & 2 Xeon Quad cores CPUs (8 cores in total).

I'm raising a virtual server in my company to hold other servers which will use my customers.

Each customer will get a server with 1GB Ram & 2 cores and will host ERP software, MS Office and some other software's. This server will use around 10 Terminal server clients.

I would like to know if my powerful server will be able to handle so many servers (60 servers) or you see here any kind of bottleneck.

I read VMware Maximums document, but I need a practical answer.

Thanks.

[curiousagain]

Thanks Troy,

one more question:

is it a limitaion of 8 VM's per core?

if I see that my Host handle 64 VM's (1 GB & 1 core per vm ) without a problem, can I add memory and create more VM's (above 8 VM's per core)?

thanks.

[JoJoGabor]

No there isnt a hard limit on number of VMs per core, there is a limit of 192 vCPUs per host. So 192 VMs - I dont think you should worry about this number

The 8 per core is just a rough guide.

As mentioned above you may not even need to increase the amount of phsyical RAM as you can overcommit.

[Troy_Clavell]

There is a configuration maximum

VI3

http://www.vmware.com/pdf/vi3_35/esx_3/r35u2/vi3_35_25_u2_config_max.pdf

>Number of virtual CPUs per core 8 (ESX Server 3.5 Update 2 and earlier).

>20 (ESX Server 3.5 Update 3 and later)

vSphere

http://www.vmware.com/pdf/vsphere4/r40/vsp_40_config_max.pdf

>Virtual CPUs per physical core 20

.

[curiousagain]

you are great, thanks a lot.

[curiousagain]

you are great, thanks a lot.

[maronep]

My 2 bits.

Good advice would be to only give you VMs 1vCPU and then monitor your guest utlilization. When you see the VMs that max out a single vCPU give only those a 2nd vCPU. This will greatly reduce your chances of cpu contention. CPU contention can be seen in esxtop under CPU (press C), look for the % RDY counter if you get an VMs with a greater > 10.0 for more and a couple of polls mean's contention could be a problem.

The other bottleneck your most likely to come across is memory overcommit, If you have an all windows guest cluster then the host page sharing should limit the possibility, but if there are different flavours of guests make sure not to overcommit on memory too much.

Disk, depending on how good yor SAN is and what you share the storage with from both vmware and the rest of your environment.

[asp24]

An 8-core host running terminal services VM's with 2 vCPU's each (ca 10 users connected with RDP to each server)? I would not run more than 10-15 of them on such a host. And 10 RDP users on one terminal server with only 1 GB of memory?

I would recommend 2-3 8-core servers with 32GB RAM (to keep costage down a little bit) for this. If not I think you will get many angry customers! Terminal servers will have MUCH more cpu load than the average server. And disk IO will be very high for 60 terminal servers with 10 users on each!

Sorry if I have misunderstood something.