[FUG-BR] Diferença absurda do mysql no Linux para o do FreeBSD

[Edson Brandi]

Bom,

Peguei 2 VMs aqui idênticas em termos de hardware virtual (rs),
rodando sobre VMWare ESXi 5.0, configuradas com 4 Gb de RAM...

Uma rodando:

FreeBSD keyserver.fug.com.br 9.0-RELEASE-p3 FreeBSD 9.0-RELEASE-p3 #0:
Tue Jun 12 01:47:53 UTC 2012
root at i386-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  i386

e na outra:

Linux server01.ebrandi.eti.br 2.6.32-220.23.1.el6.x86_64 #1 SMP Mon
Jun 18 18:58:52 BST 2012 x86_64 x86_64 x86_64 GNU/Linux

Não tinha uma VM com o FreeBSD 64 Bits aqui para testar... A
configuração e a versão do mysql é a mesma nas 2 VMs.

Os cálculos do consumo teórico de memoria em cada uma delas informado
MySQL Tuning Primer está abaixo, os numeros são bem parecidos, e vai
de encontro com aquela impressão que eu tinha de que o calculo do
Tuning Primer não olha nada do sistema operacional.

O proximo passo vai ser fazer um teste real de carga...

### FreeBSD ###

* max_connections=1

MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 2 M
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 154 M
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=10
MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 26 M
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 178 M
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=100
MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 268 M
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 420 M
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=1000
MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 2.62 G
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 2.77 G
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=4000
MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 10.49 G
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 10.64 G
Physical Memory : 1.00 G

Max memory limit exceeds 90% of physical memory

#### Linux ####

* max_connections=1

MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 2 M
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 154 M
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=10

MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 27 M
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 179 M
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=100

MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 275 M
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 427 M
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=1000
MEMORY USAGE
Max Memory Ever Allocated : 154 M
Configured Max Per-thread Buffers : 2.68 G
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 2.83 G
Physical Memory : 3.74 G
Max memory limit seem to be within acceptable norms

* max_connections=4000
MEMORY USAGE
Max Memory Ever Allocated : 157 M
Configured Max Per-thread Buffers : 10.74 G
Configured Max Global Buffers : 152 M
Configured Max Memory Limit : 10.89 G
Physical Memory : 3.74 G

Max memory limit exceeds 90% of physical memory

####