Reference

RAM Sizing

By 23rd April 2014June 9th, 2017No Comments

Table of Contents

  1. Distribution
  2. CPU Cores

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