Re: [vserver] 32bit Guests on 64bit Host

From: Ed W <lists_at_wildgooses.com>
Date: Mon 21 Dec 2009 - 12:04:30 GMT
Message-ID: <4B2F644E.1010407@wildgooses.com>

On 21/12/2009 04:37, Ghislain wrote:
> Le 20/12/2009 14:56, Herbert Poetzl a écrit :
> > On Sun, Dec 20, 2009 at 01:25:04PM
> +0100, Oliver Welter wrote:
>> Hi All,
>>
>> anybody can tell me, if there are drawbacks/issues, running 32bit
>> systems on top of a 64bit host?
>>
>> > there should be none as long as the personality is set
>> > properly and you have the 32bit compatibility enabled
>>
>
> note that we use mixed guest host and we have no major issue apart
> from an heavely used web server that see quite a lot of segfault in
> php. Personality is set to PER_LINUX32 but that still bring issues.
> However this this the only case of issues i have (it is on
> 2.6.31.3-vs2.3.0.36.18 , util-vserver: 0.30.216-pre2849). The very
> same web cluster has one system with 64bit guest that do not segfault
> at all. Setting the personality on the 32bit system removed a lot of
> them but i still get 4 per week per server at least.
>

I use gentoo 32bit hosts on some of my vservers. Actually, to moderate
that a bit, I think right now I need to say "I *did* use..", I think
they all switched to 64bit now? (Need to check)

My observation was that the 64bit vservers (nginx + fastcgi PHP)
appeared to use quite a bit more RSS and LOTS more VSS (not sure how
much this actually matters though?). I found it workable, but being on a
rented server the available ram is quite precious and it was a tough
call to move over to fully 64bit. Previously I have used a 32bit apache
+ modphp setup and not noticed any issues either (I find nginx quite a
bit easier to manage and much lighter on ram, so largely I have switched)

Certainly I never noticed a speedup/slowdown (no benchmarks done, just
observing by eye). Also I never saw any segfaults either 32bit/64bit -
I might not be watching closely enough, but I just run a basic fastcgi
cluster and it stays up for a year or so before random fluctuations
cause a reboot - not especially heavily loaded server though, from
memory it does much less than a million hits a month (probably quite a
lot less, can't even remember when I last looked at the stats...)

I can roughly say that I notice no difference between 32bit and 64bit
for basic web/email usage... My migration was from a 32bit server to a
64bit vserver host and then gradually migrating the vservers 1 by 1 to
64bit. I also used someone else's advice and swapped to making my own
base template servers and more recently also my own gentoo profiles and
this means I can very quickly spin up a new server, binary packages used
almost everywhere and the custom profiles ensure it's fast to install a
consistent suite of software across all similar types of server

Very pleased with the end result

Good luck

Ed W
Received on Mon Dec 21 12:05:24 2009

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