RAM Sizing

Picking the appropriate amount of RAM for the server depends mostly on the CPU selection. With MageStack, there is a direct relationship between CPU cores and memory utilisation; similarly, there is a relationship between the server role and memory utilisation (but this is more difficult to predict).

Distribution

On a typical, single-server set up, the ideal memory distribution is as follows

Node	Utilisation (GB)	Utilisation (%)	Utilisation (formula)
lb	1.5GB
web			cpu cores / 2GB
db		30%
mail	0.5GB
monitor	1.5GB
acc	2GB+

Eg. On an 8 core server, you could calculate memory requirements as follows

db = (( lb + mail + monitor + acc ) + ( web )) / 2
db = (( 1.5 + 0.5 + 1.5 + 2 ) + ( cpu cores / 2 )) / 2
db = (( 5.5 ) + ( 8 / 2 )) / 2
db = ( 5.5 + 4 ) / 2
db = 9.5 / 2
db = 4.75

total = lb + web + db + mail + monitor + acc
total = 1.5 + 4 + 4.75 + 0.5 + 1.5 + 2
total = 14.25GB ~16GB

CPU Cores

Chassis	CPU Cores	Required RAM (GB)	Best Allocation (GB)
E3-1270v2 / D1	8	14.25	16
E5-2643 / D2	16	20.25	32
	24	26.25	32
E5-2690 / D2	32	32.25	48
E5-2690v2 / D2	40	38.25	48
	48	44.25	48
	56	50.25	64
E5-4620/4650 / D3	64	56.25	64
	72	62.25	64
	80	68.25	128
	88	74.25	128
	96	80.25	128
	104	86.25	128
	112	92.25	128
	120	98.25	128
	128	104.25	128
	136	110.25	128
	144	116.25	128
	152	122.25	128
E7-8830/8870 / D4	160	128.25	192