Virtualization Adapted

Refer to page 136 of http://www.vmware.com/pdf/vi3_35/esx_3/r35/vi3_35_25_resource_mgmt.pdf

Some examples:

With 1 vcpu and 256MB of RAM; the VM kernel requires 87MB for 32 bit VM’s and 108MB for 64 bit VM’s.

With 8GM of RAM and 1 vCPU you’ll need 188MB and 209MB for 32 and 64 bit.

With 4 vCPU’s and 8GB of RAM you’re looking at ~360MB for a 32 bit VM and 431MB for a 64 bit VM.

Note: memory overhead for 32-bit VMs generally increased between 3.0.1 and 3.5 while 64-bit overhead generally decreased.

ESX 3.5 Overhead

ESX 3.5 Update 2
Virtual CPUs	Virtual Memory (MB)	Overhead for 32-bit VM (MB)	% Overhead for 32-bit VM	Overhead for 64-bit VM (MB)	% Overhead for 64-bit VM
1	256	87.56	34.20%	107.54	42.01%
1	512	90.82	17.74%	110.81	21.64%
1	1,024	97.35	9.51%	117.35	11.46%
1	2,048	110.40	5.39%	130.42	6.37%
1	4,096	136.50	3.33%	156.57	3.82%
1	8,192	188.69	2.30%	208.85	2.55%
1	16,384	293.07	1.79%	313.42	1.91%
1	32,768	501.84	1.53%	522.56	1.59%
1	65,536	919.37	1.40%	940.84	1.44%

2	256	108.73	42.47%	146.41	57.19%
2	512	114.49	22.36%	152.20	29.73%
2	1,024	126.04	12.31%	163.79	16.00%
2	2,048	149.11	7.28%	186.96	9.13%
2	4,096	195.27	4.77%	233.30	5.70%
2	8,192	287.57	3.51%	325.98	3.98%
2	16,384	472.18	2.88%	511.34	3.12%
2	32,768	841.40	2.57%	882.06	2.69%
2	65,536	1579.84	2.41%	1623.50	2.48%

4	256	146.75	57.32%	219.82	85.87%
4	512	153.52	29.98%	226.64	44.27%
4	1,024	167.09	16.32%	240.30	23.47%
4	2,048	194.20	9.48%	267.61	13.07%
4	4,096	248.45	6.07%	322.22	7.87%
4	8,192	356.91	4.36%	431.44	5.27%
4	16,384	573.85	3.50%	649.88	3.97%
4	32,768	1007.73	3.08%	1086.75	3.32%
4	65,536	1875.48	2.86%	1960.52	2.99%

	Averages	408.30	11.51%	453.30	15.29%

ESX 3.0 Overhead

vcpu	vRAM	32 bit overhead	64 bit overhead
1	256	79	174
1	512	79	176
1	1024	84	180
1	2048	91	188
1	4096	107	204
1	8192	139	236
1	16384	203	300
2	256	97	288
2	512	101	292
2	1024	101	300
2	2048	125	316
2	4096	157	349
2	8192	221	413
2	16384	349	541
4	256	129	511
4	512	133	515
4	1024	141	523
4	2048	157	540
4	4096	189	572
4	8192	222	605
4	16384	350	734

Here’s an example hosts.allow:
#begin
sshd:management.host.com:allow
sshd:ALL:deny
xinetd:management-host-ip-or-fqdn-hostname:allow
xinetx:ALL:deny
httpd:management-host-ip-or-fqdn-hostname:allow
httpd:ALL:deny
#eof
But even this may be too simple.

Reference:

http://www.dell.com/downloads/global/…/tnc/dell_vmware_certified_deploy.pdf

http://communities.vmware.com/thread/182964?tstart=0

What this will do is allow all hosts to ssh into the system while only allowing VI client connections from the virtualcenter server. This means you pretty much have to go through virtualcenter to manage the system.