32 bit vs. 64 bit OS - advantages other than additional memory?

Vibe

Verified User
Joined
Aug 3, 2005
Messages
124
Hi everyone,

Pardon me if this question has already been answered in the forum - I have searched here and Google but haven't found the information I was looking for.

I was hoping to learn more about the advantages/disadvantages of using a 64 bit vs. 32 bit OS with regard to the hosting services that we all provide. I find a lot of info regarding application development and desktop usage - but not a lot with regard to "standard" web services - e.g. Apache/PHP/MySQL/Exim etc.

I understand the benefits of having the ability to access additional memory e.g. beyond the 4GB "limit." However, in my situation, I'm not certain if the move to 64 bit OS would be of any benefit.

For example - we host on inexpensive Dell 860 1U servers using 32 bit FreeBSD (6.2 eventually moving to 7.1) with 2 GB of memory. An example of server resources utilized >>> current "active" memory on one machine is at a maximum of 500-600MB with "inactive" averages of 1GB. Processor usage averages around 5-8% which is pretty standard. We aren't running SpamAssassin (mail filtering is offloaded to spam/virus appliance) and everything runs very smoothly. Obviously we are not hosting any sites that draw a large audience :D.

Soon we will be bringing onboard another server (whoo hoo the big #3 - call us mighty!!! :p ) and are contemplating the move to 64bit. Are there any benefits that I can look forward to moving in this direction?

In other posts (which of course I can't find now) people have mentioned that they stick to 32 bit for stability reasons - is there any truth to this?

It appears that 64 bit is the direction that technology is heading - I am just curious if the potential issues that arise don't outweigh the benefits.

P.S. I know DA does not "officially" support 64 bit FreeBSD - however, those that have been successful have encouraged us to make a trial attempt at it.

Thanks for any input you can provide!!!
 
Is anyone using a 64 bit OS for anything other than increased memory?
 
It is not true that you need 64bit kernel & libs to reach more than 4GB of RAM, at least not with a 2.6 linux kernel: you just need to activate the kernel option CONFIG_HIGHMEM64G and you can go to 64G without any problem.
I'm not sure about FreeBSD, instead I know it's not possible with Windows XP/2k (who cares?).

64bit just means that there are more (ideally much, much more) possible addresses and functions, which means that you can achieve more in less time.
In reality the difference is often imperceptible, because few libraries already make use of those functions, and compilers need years to adjust their machine code results for the best.
On the other hand, there isn't much reason to say no to 64bits, unless you still need 32bit libraries for some closed source shared precompiled program (like DA) or there is some less stable kernel module or application. Sometimes you just don't have the choice, for example with closed source precompiled 32bit kernel modules.

It's up to every administrator to find what's compatible, what's less stable and judge which one is best for his needs.
 
Back
Top