Linode Forum
Linode Community Forums
 FAQFAQ    SearchSearch    MembersMembers      Register Register 
 LoginLogin [ Anonymous ] 
Post new topic  Reply to topic
Author Message
PostPosted: Tue May 11, 2010 4:56 pm 
Offline
Senior Member

Joined: Wed May 13, 2009 1:32 pm
Posts: 737
Location: Italy
Hi,
is there someone who tryed out the difference on a fresh install of CentOS running LAMP on both 32 and 64bit?

What is the available quantity of ram for both os version?
Thanks.


Top
   
 Post subject:
PostPosted: Wed May 12, 2010 10:56 am 
Offline
Senior Member
User avatar

Joined: Tue May 26, 2009 3:29 pm
Posts: 1691
Location: Montreal, QC
There will be less RAM on the 64-bit version, since 64-bit processes require more RAM.

Unless you're buying a Linode with more than 3 or 4 gigs of RAM, you probably don't want/need 64-bit.

If you're new to Linux, you may also want to consider Ubuntu Server rather than CentOS, as it's far more popular and as a result has far more community documentation and assistance available.


Top
   
 Post subject:
PostPosted: Wed May 12, 2010 11:01 am 
Offline
Senior Member

Joined: Wed Feb 13, 2008 2:40 pm
Posts: 126
I'd say RHEL is more popular on the server than Ubuntu, and I know it has lots of documentation and community questions.


Top
   
 Post subject:
PostPosted: Wed May 12, 2010 11:02 am 
Offline
Senior Member

Joined: Wed May 13, 2009 1:32 pm
Posts: 737
Location: Italy
Guspaz wrote:
There will be less RAM on the 64-bit version, since 64-bit processes require more RAM.

Unless you're buying a Linode with more than 3 or 4 gigs of RAM, you probably don't want/need 64-bit.

If you're new to Linux, you may also want to consider Ubuntu Server rather than CentOS, as it's far more popular and as a result has far more community documentation and assistance available.


I'm using RedHat since RedHat4, I prefer CentOS for this but you don't answered my questions.
I would like to know how much RAM a LAMP server (configured in the same way on both 32 and 64 bit OS) eats on both platform.


Top
   
 Post subject:
PostPosted: Wed May 12, 2010 12:11 pm 
Offline
Senior Member

Joined: Sat Mar 28, 2009 4:23 pm
Posts: 415
Website: http://jedsmith.org/
Location: Out of his depth and job-hopping without a clue about network security fundamentals
Guspaz wrote:
Unless you're buying a Linode with more than 3 or 4 gigs of RAM, you probably don't want/need 64-bit.

Don't need it then, either. PAE, unless you're committing a >3GB (or 2GB?) working set of data in one application. In most workloads, like, say, worker MPM in Apache 2, each process will be able to take advantage of a few gigs itself. The OS will use the extra RAM for page cache regardless.

sblantipodi wrote:
I would like to know how much RAM a LAMP server (configured in the same way on both 32 and 64 bit OS) eats on both platform.

I was curious myself, so I deployed this StackScript on both CentOS 5.4 i686 and CentOS 5.4 x86_64; after all, just how much higher is the memory demand with the pointer overhead? Nothing was changed beyond how the StackScript booted the system.

Code:
CentOS release 5.4 (Final)                                                                          
Kernel 2.6.32.12-linode25 on an i686

li184-10 login: root
Password:
[root@li184-10 ~]# free -m                                                                         
             total       used       free     shared    buffers     cached                           
Mem:           348        280         67          0          8        221                           
-/+ buffers/cache:         50        297                                                           
Swap:          255          0        255           


Doing 131.72 requests/sec during ab -n 100000 -c 100 http://... from a different location (intentionally network-bound so it was a light load):

Code:
             total       used       free     shared    buffers     cached                           
Mem:           348        293         54          0          8        224                           
-/+ buffers/cache:         60        288                                                           
Swap:          255          0        255


Reboot into x86_64...

Code:
CentOS release 5.4 (Final)                                                                          
Kernel 2.6.32.12-x86_64-linode12 on an x86_64                                                       
                                                                                                   
li184-10 login: root                                                                               
Password:                                                                                           
[root@li184-10 ~]# free -m                                                                         
             total       used       free     shared    buffers     cached                           
Mem:           343        328         15          0          8        237                           
-/+ buffers/cache:         81        261                                                           
Swap:          255          0        255


Huh. Again, under ab:

Code:
             total       used       free     shared    buffers     cached                           
Mem:           343        338          4          0          8        234                           
-/+ buffers/cache:         95        248                                                           
Swap:          255          0        255


Interesting result.

_________________
Disclaimer: I am no longer employed by Linode; opinions are my own alone.


Top
   
 Post subject:
PostPosted: Wed May 12, 2010 12:24 pm 
Offline
Senior Member

Joined: Wed May 13, 2009 1:32 pm
Posts: 737
Location: Italy
jed wrote:
Guspaz wrote:
Unless you're buying a Linode with more than 3 or 4 gigs of RAM, you probably don't want/need 64-bit.

Don't need it then, either. PAE, unless you're committing a >3GB (or 2GB?) working set of data in one application. In most workloads, like, say, worker MPM in Apache 2, each process will be able to take advantage of a few gigs itself. The OS will use the extra RAM for page cache regardless.

sblantipodi wrote:
I would like to know how much RAM a LAMP server (configured in the same way on both 32 and 64 bit OS) eats on both platform.

I was curious myself, so I deployed this StackScript on both CentOS 5.4 i686 and CentOS 5.4 x86_64; after all, just how much higher is the memory demand with the pointer overhead? Nothing was changed beyond how the StackScript booted the system.

Code:
CentOS release 5.4 (Final)                                                                          
Kernel 2.6.32.12-linode25 on an i686

li184-10 login: root
Password:
[root@li184-10 ~]# free -m                                                                         
             total       used       free     shared    buffers     cached                           
Mem:           348        280         67          0          8        221                           
-/+ buffers/cache:         50        297                                                           
Swap:          255          0        255           


Doing 131.72 requests/sec during ab -n 100000 -c 100 http://... from a different location (intentionally network-bound so it was a light load):

Code:
             total       used       free     shared    buffers     cached                           
Mem:           348        293         54          0          8        224                           
-/+ buffers/cache:         60        288                                                           
Swap:          255          0        255


Reboot into x86_64...

Code:
CentOS release 5.4 (Final)                                                                          
Kernel 2.6.32.12-x86_64-linode12 on an x86_64                                                       
                                                                                                   
li184-10 login: root                                                                               
Password:                                                                                           
[root@li184-10 ~]# free -m                                                                         
             total       used       free     shared    buffers     cached                           
Mem:           343        328         15          0          8        237 begin_of_the_skype_highlighting              343 328 15 0 8 237      end_of_the_skype_highlighting                           
-/+ buffers/cache:         81        261                                                           
Swap:          255          0        255


Huh. Again, under ab:

Code:
             total       used       free     shared    buffers     cached                           
Mem:           343        338          4          0          8        234                           
-/+ buffers/cache:         95        248                                                           
Swap:          255          0        255


Interesting result.


this is really interesting... thanks, really thanks.


Top
   
 Post subject:
PostPosted: Mon May 17, 2010 5:40 pm 
Offline
Senior Member

Joined: Wed May 13, 2009 1:32 pm
Posts: 737
Location: Italy
reading this it seems that 64bit give some good improvements also with LAMP.
http://www.scribd.com/doc/363677/Benchm ... ode-Ubuntu

this is quite different from the usual saying...


Top
   
 Post subject:
PostPosted: Mon May 17, 2010 6:36 pm 
Offline
Senior Member
User avatar

Joined: Fri Dec 11, 2009 7:09 pm
Posts: 168
sblantipodi wrote:
reading this it seems that 64bit give some good improvements also with LAMP.
http://www.scribd.com/doc/363677/Benchm ... ode-Ubuntu

this is quite different from the usual saying...


Well- I would expect better performance with 1gb of ram, but that really doesn't address a low memory machine.

_________________
--
Chris Bryant


Top
   
 Post subject:
PostPosted: Mon May 17, 2010 7:09 pm 
Offline
Senior Member
User avatar

Joined: Tue Apr 13, 2004 6:54 pm
Posts: 833
sblantipodi wrote:
reading this it seems that 64bit give some good improvements also with LAMP.
http://www.scribd.com/doc/363677/Benchm ... ode-Ubuntu

this is quite different from the usual saying...

With sufficient resources, 64bit may be better. _MAY_

linode's typically are resource limited and you get better performance with 32bit.

_________________
Rgds
Stephen
(Linux user since kernel version 0.11)


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
RSS

Powered by phpBB® Forum Software © phpBB Group