32bit vs 64bit Linux

[Eric Shubert]

Hey Paul,

I'm not a fan of OpenVZ either. Just thought I'd mention it since it's
an option with PVE.  While it's not much more than chroot on steroids
(afaict), (openvz) containers do run with less overhead than KVMs. This
difference is diminishing though as KVM code matures (iow, in later
kernel versions).

I'll have to rethink my using 32-bit KVMs. This might be penny wise and
pound foolish. I've been working in SMB environments with 8G max hosts
though. With larger platform hosts (32G+) it probably makes sense to
make all KVMs 64-bit. Still, I don't see an authoritative DNS server
ever needing >3G of ram.  As server roles and tasks are divided, each
KVM tends to be smaller. I may be overly concerned about ram, but I'd
like to know more precisely than I do about how much is wasted by going
to 64-bit. I should do some side-by-side comparisons. It scares me a
little though, like having a ton of small (symlink sized) files on a
drive with 4k sectors. Probably my conservative nature.

Thanks Paul!

-- 
-Eric 'shubes'

On 05/31/2013 01:57 PM, Paul Mooring wrote:
> While I'm not a fan of OpenVZ and I never run any 32 bit guests regardless of size, I think virtualizing everything is great advice for most production environments.  I tend to still run all my database servers on bare metal, but my web proxies (nginx, apache or haproxy) are all virtual as well as all my app servers (php-fpm, unicorn, unicorn).  This gives you a lot of flexibility to move resources around as needed.
>
> Paul Mooring
> Operations Engineer
> www.opscode.com
>
> ________________________________________
> From: plug-discuss-bounces at lists.phxlinux.org on behalf of Eric Shubert
> Sent: Friday, May 31, 2013 1:40 PM
> To: Main PLUG discussion list
> Subject: Re: 32bit vs 64bit Linux
>
> On 05/31/2013 09:28 AM, keith smith wrote:
>>
>> Hi,
>>
>> Even though I have 64bit hardware I always install the 32bit version of
>> Linux.  I do so because of the past discussions on this list that made
>> me believe the 32bit OS was better because 64bit caching is actually
>> slower due to the requirement that the cache be filled to a certain
>> point before it is moved.  I think I recall something about the amount
>> of RAM having some effect here also.
>>
>> Using a 32bit version over a 64bit version seems counter intuitive,
>> however that is what I have taken away from these conversations about
>> 32bit vs 64bit Linux.
>>
>> I'm using CentOS 6.x on a LAMP server that gets a low amount of
>> traffic.   However I may make the jump to Linux on my desktop this
>> summer. (this will be my 3rd attempt to become M$ free except one VM so
>> I can use IE for testing) I think all of my hardware is 64bit.
>>
>> So that begs the question, is 32bit better than 64bit or do I not
>> understand the issue?
>>
>> Thank you for your feedback.
>>
>> Keith
>>
>> ------------------------
>> Keith Smith
>>
>>
>>
>
> Rule of thumb for servers: use a 64-bit host (PVE for example), and
> virtualize everything to run under it. Use 32-bit for KVMs unless they
> need >3G of RAM. OpenVZ contains will of course run 64-bit, as they
> share the kernel.
>
> There are no doubt exceptions to this, but it's a good start.
>
> For a LEMP server, you may want to consider separating EMP into 3
> separate hosts. Doing it this way, you could have both a PHP51 host and
> a PHP53 host (LEMPP?), and let your (E)nginx host determine which one to
> use based on the url (reverse proxy configuration).
>
> Having things on a virtual platform opens up a lot of possibilities you
> don't have otherwise. The list is extensive. :)
>
> --
> -Eric 'shubes'
> ---------------------------------------------------
> PLUG-discuss mailing list - PLUG-discuss at lists.phxlinux.org
> To subscribe, unsubscribe, or to change your mail settings:
> http://lists.phxlinux.org/mailman/listinfo/plug-discuss
>