Re: LuaJIT-on-Xen?
- From: Justin Cormack <justin@xxxxxxxxxxxxxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Sun, 5 May 2013 13:46:18 +0100
On Sun, May 5, 2013 at 1:00 PM, Alexander Gladysh <agladysh@xxxxxxxxx> wrote:
> I mean that we were *not* happy with the level of isolation that
> OpenVZ provided (several years ago).
>
> Are there any texts documenting experience with LXC under high load
> scenarios? I'm especially interested in rationing HDD between several
> VMs (containers?), including a few very aggressive HDD users.
>
> In our experience, this is somewhat problematic even for Xen (but it
> is possible that we don't wield it good enough).
Seriously just get SSD. You cannot expect to ration 100iops sanely
between multiple processes and get anything much useful for aggressive
users. Suspect you have marginally more control under lxc as all the
requests are seen by the same kernel. You end up with pretty much the
same tools, or you can customise the elevator. But an SSD is much more
useful.
>> in fact, this project would be almost trivial with LXC, since a
>> container starts with an arbitrary process that becomes the root of
>> the subtee, and looks like PID#1 "from inside". if that process is
>> "init", and you give it a full installation in the chroot, then you
>> have a new OS in a VM. if it's any other proces (say, a LuaJIT
>> worker!) then it's a lot simpler, like a better chroot
>
> Well, yes. But will the isolation be good enough?
Security isolation or performance?
> We hit many kinds of pitfalls with Xen (and with OpenVZ earlier), so
> I'm wary about adopting yet another virtualization scheme... That
> being said, we're already using LXC at a very basic level (mostly in
> development / testing scenarios where we need to emulate Xen cluster
> without paying the full cost), and plan to use it more, so it is not
> *that* alien and unknown. :-)
>
Linux containers are not really a virtualisation scheme per se, it is
a set of kernel tools for process resource control (namespaces,
cgroups) which the lxc project dresses up like virtualisation, but it
is better to consider it a toolset.
Justin
Other related posts:
