Linode 360, CentOS LAMP, 32 bit and 64 bit, RAM comparison.
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.
8 Replies
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.
@Guspaz:
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.
@Guspaz:
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:
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 deployedon 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. this StackScript
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):
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…
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:
total used free shared buffers cached
Mem: 343 338 4 0 8 234
-/+ buffers/cache: 95 248
Swap: 255 0 255
Interesting result.
@jed:
@Guspaz: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: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 deployedon 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. this StackScriptCentOS 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 255Doing 131.72 requests/sec during ab -n 100000 -c 100 http://… from a different location (intentionally network-bound so it was a light load):
total used free shared buffers cached Mem: 348 293 54 0 8 224 -/+ buffers/cache: 60 288 Swap: 255 0 255Reboot into x86_64…
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 255Huh. Again, under ab:
total used free shared buffers cached Mem: 343 338 4 0 8 234 -/+ buffers/cache: 95 248 Swap: 255 0 255Interesting result.
this is really interesting… thanks, really thanks.
this is quite different from the usual saying…
@sblantipodi:
reading this it seems that 64bit give some good improvements also with LAMP.
http://www.scribd.com/doc/363677/Benchm … ode-Ubuntu">http://www.scribd.com/doc/363677/Benchmarks-AMD64-in-32bit-mode-vs-64bit-mode-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.
@sblantipodi:
reading this it seems that 64bit give some good improvements also with LAMP.
http://www.scribd.com/doc/363677/Benchm … ode-Ubuntu">http://www.scribd.com/doc/363677/Benchmarks-AMD64-in-32bit-mode-vs-64bit-mode-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.