Re: [gentoo-server] Toughts on Virtualization

[Pandu Poluan <pandu@poluan.info>]

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On Apr 9, 2012 12:49 AM, "Vinícius Ferrão" <viniciusferrao@cc.if.ufrj.br>
wrote:
>
> Hello fellas,
>
> I'm considering to implement some Gentoo Servers on top of VMWare vSphere
ESXi. But perhaps this is not the best option.
>
> I was googling about performance issues in this scenario and started to
consider some OS-Level VT, like OpenVZ or Linux-vserver, or whatever else.
>
> So I'm here to ask some opinions about virtualization.
>
> My restricted set of rules (LOL):
> 1. I will not run anything else than Linux.
> 2. I don't care about GPL, BSD, Icecream, Bacon, or whatever license,
since it's free, it's fine.
> 3. Don't need to be an Opensource solution.
>
> Thanks for any help,
>

I've deployed more than 20 Gentoo servers over VMware and XenServer, no
performance issues.

From the top of my head, Some pointers when doing menuconfig:

* Go "tickless"
* Activate the relevant paravirtualization code; choose the
hypervisor-friendly suspend instead of spinlock
* Use the paravirtualized storage driver (Vmware PV-SCSI or Xen Block
FrontEnd)
* If using hardened, first configure for "virtualization", exit (and save),
menuconfig again, and check the options under GrSec and PaX; there are
options that will cause performance penalty when run on top of a hypervisor
(see the help text)
* Do not compile *any* unnecessary drivers (e.g., wireless support, exotic
devices)
* Use I/O without delay

And, deployment-wise :

* When possible, do not create more than one partition per virtual drive;
instead, create 1 virtual drive per filesystem mountpoint. E.g. :

Instead of having /dev/sda{1,2,3,4} for /boot, /, /usr, and /home,
respectively, create 4 virtual drives instead. The above mointpoints will
then respectively map to /dev/sd{a,b,c,d}1

(The reason for the latter is because partitions get handled by the VM
(slower), while accesses to virtual hard disks are handled by the
hypervisor (faster)).

I don't have access to my Gentoo systems ATM, so I can't provide a more
detailed guide.

Rgds,

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