# Jails and CPU, RAM AND MORE



## Wolfi83 (Sep 14, 2011)

Hello,

If I create some jails on my host system, is there then any loss of CPU, RAM or other? I mean do all running jails need their own RAM? If so, how much and do they need much CPU?


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## graudeejs (Sep 14, 2011)

Each jails is like new FreeBSD (except it doesn't need memory for kernel)
But remember, FreeBSD really needs very little memory itself


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## Wolfi83 (Sep 14, 2011)

Hi, 

thanks and what is about the cpu usage for every new jail?
does any jail have his own kernel?


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## graudeejs (Sep 14, 2011)

No, all jails use hosts kernel (don't ask me how, I'm not into technical details)
Other than kernel and devices, everything else is independent, so yes, programs do use CPU, but it's very lightweight, so don't bother your brain with such question. Just try it


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## da1 (Sep 14, 2011)

The jail itself has no overhead, in terms of CPU, RAM, etc but these are directly dependent on the application running inside the jail. For instance, if you plan on having a large NAS, expect high HDD utilization. On the other hand, if you plan on running munin inside the jail (with many nodes), expect high CPU usage (due to graph computation).

Again, the amount of resources used by the jail is directly dependent on the application(s) running inside it.


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## Wolfi83 (Sep 14, 2011)

thanks i just want to run mysql, apache and other in a extra jail not a nas 

thanks


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