32 or 64 bit?

Patsjoelie

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Hi all ...
I'm getting myself a new dedicated server with centos 5.3.
Now I'm thinking, should i get 32 or 64 bit?
Accounts from my current server (fedora 5) will be migrated to this server.
Should i expect any problems?

thanks in advance for any response!
Have a great day!
Pat.
 

nobaloney

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How much memory are you getting? Are you planning on ever going above 3 GB on this server? If so, you'll benefit from 64 bit. You shouldn't encounter any difficulties moving from Fedora to CentOS depending on the version numbers of the software in your hosting stack.

Jeff
 

Patsjoelie

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Thanks for your time and response Jeff.
Currently this server will have 2Gb RAM.
Since it is a "ready to go" server, I don't expect this one will ever have more memory.

Thanks again, have a great day!
Pat.
 

floyd

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I can use up to 4 GB of ram on 32 bit CentOS using the PAE kernel.
 

floyd

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Don't you mean you can use more than 4GB ? is it not up to 64GB using PAE ?
I was relating my personal experience not stating general specifications.

I can use up to 4 GB of ram
That is what I have done.

I have not needed a board that could handle 64 GB of ram yet so I cannot say if PAE will work with it or not.

But that is great to know. Thanks.
 

nobaloney

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Back to the original question: if you're never going above 2 GB of memory, then there's no reason to go to a 64-bit system.

Note that even without a PAE kernel you can use up to 3.5 GB of 4 GB installed with a 32-bit system.

We still have a lot of 32-bit systems installed and running fine without problems.

Jeff
 

floyd

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Note that even without a PAE kernel you can use up to 3.5 GB of 4 GB installed with a 32-bit system.
So is top lying to me?

Code:
top - 22:09:27 up 92 days,  8:24,  2 users,  load average: 1.16, 0.72, 0.47
Tasks: 201 total,   3 running, 196 sleeping,   0 stopped,   2 zombie
Cpu0  : 10.4%us,  2.0%sy,  0.1%ni, 85.3%id,  2.2%wa,  0.0%hi,  0.1%si,  0.0%st
Cpu1  : 16.9%us,  2.6%sy,  0.1%ni, 78.3%id,  2.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  : 11.1%us,  2.1%sy,  0.1%ni, 84.6%id,  2.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu3  : 14.2%us,  2.7%sy,  0.1%ni, 80.8%id,  2.0%wa,  0.1%hi,  0.2%si,  0.0%st
Mem:   4139820k total,  3850748k used,   289072k free,   317356k buffers
Swap:   522104k total,     7700k used,   514404k free,  2503008k cached
Code:
top - 22:11:35 up 2 days, 16:46,  1 user,  load average: 1.21, 1.24, 1.38
Tasks: 229 total,   1 running, 228 sleeping,   0 stopped,   0 zombie
Cpu0  : 26.0%us,  6.7%sy,  0.0%ni, 53.7%id, 13.1%wa,  0.0%hi,  0.4%si,  0.0%st
Cpu1  : 10.2%us,  4.8%sy,  0.0%ni, 82.3%id,  2.6%wa,  0.0%hi,  0.1%si,  0.0%st
Cpu2  : 12.4%us,  4.9%sy,  0.1%ni, 80.8%id,  1.7%wa,  0.0%hi,  0.1%si,  0.0%st
Cpu3  :  8.2%us,  3.1%sy,  0.0%ni, 84.1%id,  4.3%wa,  0.0%hi,  0.2%si,  0.0%st
Mem:   4081728k total,  3756476k used,   325252k free,   155168k buffers
Swap:  1020024k total,       60k used,  1019964k free,  2137100k cached
I do not have any problems with 32 bit systems either.
 

nobaloney

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On all the machines we've run with 4GB with a 32-bit Linux OS, the system has held back the last half GB for system use. Perhaps because they've all been desktop systems.

I stand corrected.

Jeff
 

R1Lover

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No matter how much ram you have you will benifit from a 64 bit system... it's night and day from my experience.

I just moved one server from 32 bit to 64 bit on the same hardware and there was a large improvement.
 

R1Lover

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Correct me if I'm wrong but that article is about desktops and not servers.... big difference imo right?
 

floyd

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Correct me if I'm wrong but that article is about desktops and not servers.... big difference imo right?
RAM - If you plan on using a machine that has more than 4GB of RAM, you'll need to use the 64-bit version of your distribution because 32-bit operating systems are only able to handle up to 4GB, maximum*. There's just not enough memory addresses for more. This is usually not a problem for desktop users, but it might be a concern for servers or high-end workstations.
This is the only place it mentions a desktop. It also mentions servers so the article is for both.
 

youds

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No problems here with 5.3 64bit and have just done a fresh install :)
 

Nexxterra.com

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How difficult to change...

I bought a server that was 64bit, then was informed that DA and installatron both did not support the 64 bit system....
Fast forward a couple years... Now they both do, How difficult would it be to convert to a 64 bit server?
Could I run a da backup, re do the server (centos 64 bit, etc, etc)and restore the back up or would I have to do way, more....
This would need to be done at night, and be online by the early morning, so every variable would need to be considered first...
Server has dual quad processors, and many other features with 64bit in mind
 

nobaloney

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It should work for you; to avoid any unforseen issues you may want to hire someone to do it for you so all you have to do is be available to re-install the OS.

Don't forget to make a list of any additional software you've installed over the years, because it will have to be reinstalled as well.

Jeff
 

desynced

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Just my 2 cents on the subject, the whole reason I changed my servers from Ensim to DirectAdmin is because of the 64 bit support. Even though Ensim claims to support 64 bit OS, I had headaches after headaches after headaches from bugs/quirks with the 64bit CentOS and Ensim. NONE of which I have had with DirectAdmin.

As for improvements, we have 12 Dell Poweredge servers that we've ordered with the exact same specs except for the amount of memory. 8 of them running 64bit CentOS 5.3 and the other 4 are running the 32 bit version. There is a *slight* improvement on the 64bit servers over the 32bit that have the heaviest loads. We've compared both that have the exact same hardware and the 64bit does yum updates faster (when installing the packages themselves) and the 64bit version does load heavy MySQL/PHP scripts (usually forums) faster. Also running game servers like Team Fortress 2 and others doesnt show *that much* of an improvement over the two. Not enough to rush out and upgrade every 32bit server you have to 64bit.

As for memory, 2 of the 4 32 bit CentOS servers are running at 8GB of memory with the PAE kernel and have been running fine (though some scripts will only report you only have 3.5GB or 4GB of memory, your server is running at the full 8GB of memory. This is a flaw in the scripts themselves and not your server.). The latest phpsysinfo does show the correct memory installed.

We do have one current issue between the two though with the DA servers. Once in a while, web pages will not load until you refresh and then it comes up fine. This is only happening on the 64bit servers and hasnt been reported on any of the 32bit servers. But this only happens once in a while at random (usually during the peak times for the servers). We're currently investigating this issue.
 
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