8G RAM in 32bit platform

[Patrick T. Tsang]

Hello,

Sorry, I didn't mention it is Redhat AS5.0

The bigsmp no longer exists.

Anyone tried 32bits Redhat AS5.0 with 8G RAM for cyrus imapd?

Thanks
Patrick



----- Original Message ----- 
From: "David Carter" <dpc22 at cam.ac.uk>
To: "Patrick T. Tsang" <patrick at patricktsang.net>
Cc: <info-cyrus at lists.andrew.cmu.edu>
Sent: Friday, July 13, 2007 5:24 PM
Subject: Re: 8G RAM in 32bit platform


> On Fri, 13 Jul 2007, Patrick T. Tsang wrote:
>
>> We will start up the mail server with 4G RAM.
>> As I know the 32bits cannot handle RAM more than 3.2G.
>>
>> The client plans to upgrade the RAM to 8G in coming years.
>> Can the 64bits platform is the only solution to it?
>
> You don't say which CPU or operating system you are using.
>
> The Linux bigsmp kernel supports PAE extensions on IA32 platforms: all 8 
> GBytes will be available as buffer cache, which is what matters to Cyrus.
>
> 64 bit pointers don't really do anything: no single process in Cyrus needs 
> 2 GBytes of address space. 64 bit integer arithmetic would be a slight 
> benefit for quota arithmetic (unsigned long long). However my systems 
> spend about 2% of their time in user CPU state according to vmstat. You 
> really aren't going to notice on any modern Intel/AMD CPU.
>
> -- 
> David Carter                             Email: David.Carter at ucs.cam.ac.uk
> University Computing Service,            Phone: (01223) 334502
> New Museums Site, Pembroke Street,       Fax:   (01223) 334679
> Cambridge UK. CB2 3QH.
>