Hello,
I have a centos 5.2 core 2 duo 3.0 GHZ with 2 GB ram which is working as a Virtual machine. i've just upgraded the hosting physical server from 32 GB to 64 GB of ram. which in turn, would require me to upgrade the VM to 8 GB. this is a 32 bit centos installation, would the system recognize and use the 8 GB? the option of using a 64 bit centos isnt possible.
So i'm turning to you for advice. would upgrading the Ram be enough, or is there anything to be done that's kernel based of some sort?
best,
--Roland
On Tue, 14 Sep 2010 09:44:28 +0300 Roland RoLaNd r_o_l_a_n_d@hotmail.com wrote:
Hello,
I have a centos 5.2 core 2 duo 3.0 GHZ with 2 GB ram which is working as a Virtual machine. i've just upgraded the hosting physical server from 32 GB to 64 GB of ram. which in turn, would require me to upgrade the VM to 8 GB. this is a 32 bit centos installation, would the system recognize and use the 8 GB?
Yes, using a PAE enabled kernel. Anyway, apps won't be able to use more than 3GB per process. Welcome in 32 bits limitations.
the option of using a 64 bit centos isnt possible.
Strange. 64 bits is here for years, 64 runs 32 bits code perfectly.
So i'm turning to you for advice. would upgrading the Ram be enough, or is there anything to be done that's kernel based of some sort?
Either PAE or switch to 64 bits. There's no other path. HTH,
On Tue, 14 Sep 2010 10:01:52 +0100 Kevin Thorpe kevin@pibenchmark.com wrote:
Strange. 64 bits is here for years, 64 runs 32 bits code perfectly.
Not always. 32 bit support is good but we had a program here which I couldn't get to work any way up.
Oh ? which one ? We've switched to 64 during C4.0 days, never had a problem since with codes we couldn't port.
Thanks for your feedback..
So if i set my VM to 8 GB, each proccess would use a max of 3 GB (even with PAE installed and selected on boot)?
Date: Tue, 14 Sep 2010 08:50:18 +0200 From: l.wandrebeck@gmail.com To: centos@centos.org CC: r_o_l_a_n_d@hotmail.com Subject: Re: [CentOS] Centos Virtual Machine 32 bit with 8 GB ram ?
On Tue, 14 Sep 2010 09:44:28 +0300 Roland RoLaNd r_o_l_a_n_d@hotmail.com wrote:
Hello,
I have a centos 5.2 core 2 duo 3.0 GHZ with 2 GB ram which is working as a Virtual machine. i've just upgraded the hosting physical server from 32 GB to 64 GB of ram. which in turn, would require me to upgrade the VM to 8 GB. this is a 32 bit centos installation, would the system recognize and use the 8 GB?
Yes, using a PAE enabled kernel. Anyway, apps won't be able to use more than 3GB per process. Welcome in 32 bits limitations.
the option of using a 64 bit centos isnt possible.
Strange. 64 bits is here for years, 64 runs 32 bits code perfectly.
So i'm turning to you for advice. would upgrading the Ram be enough, or is there anything to be done that's kernel based of some sort?
Either PAE or switch to 64 bits. There's no other path. HTH,
On Tue, 14 Sep 2010 16:45:50 +0300 Roland RoLaNd r_o_l_a_n_d@hotmail.com wrote:
Thanks for your feedback..
So if i set my VM to 8 GB, each proccess would use a max of 3 GB (even with PAE installed and selected on boot)?
PAE allows a 32 bits host to see more than 4GB of ram. but each process is still limited to ~3gb. To dive a bit more into technical details, PAE is like EMS in DOS time. In EMS, you saw the whole ram, but couldn't allocate more than 64KB per process. With PAE, the same, with a limit of 4GB-OS stuff per process, so it gives something like 3GB. Hope I'm clear.
On Tue, Sep 14, 2010 at 3:58 PM, Laurent Wandrebeck l.wandrebeck@gmail.com wrote:
On Tue, 14 Sep 2010 16:45:50 +0300 Roland RoLaNd r_o_l_a_n_d@hotmail.com wrote:
Thanks for your feedback..
So if i set my VM to 8 GB, each proccess would use a max of 3 GB (even with PAE installed and selected on boot)?
PAE allows a 32 bits host to see more than 4GB of ram. but each process is still limited to ~3gb. To dive a bit more into technical details, PAE is like EMS in DOS time. In EMS, you saw the whole ram, but couldn't allocate more than 64KB per process. With PAE, the same, with a limit of 4GB-OS stuff per process, so it gives something like 3GB. Hope I'm clear. -- Laurent Wandrebeck GPG fingerprint/Empreinte GPG: F5CA 37A4 6D03 A90C 7A1D 2A62 54E6 EF2C D17C F64C
Even so, most machines today performs multiple tasks, so 3GB limit per process isn't really that big an issue, unless you render graphics with a mono-threaded application.
On servers you generally have more than one process running so the whole experience will sitll be a good one with 4GB+ RAM, upto 32GB if memory serves me right?
On Tue, 14 Sep 2010 16:01:13 +0200 Rudi Ahlers Rudi@SoftDux.com wrote:
Even so, most machines today performs multiple tasks, so 3GB limit per process isn't really that big an issue, unless you render graphics with a mono-threaded application.
Depends the domain :) We work in satellite images processing here, so 3GB per process is an issue. Moreover, PAE memory access is far from optimal. You're better run a 64 bits OS with 32 apps than a 32 bits PAE enables, imho.
On servers you generally have more than one process running so the whole experience will sitll be a good one with 4GB+ RAM, upto 32GB if memory serves me right?
Don't know about upper limit of PAE. Wikipedia says 64GB. Regards,
On Tue, 2010-09-14 at 16:19 +0200, Laurent Wandrebeck wrote:
On Tue, 14 Sep 2010 16:01:13 +0200 Rudi Ahlers Rudi@SoftDux.com wrote:
Even so, most machines today performs multiple tasks, so 3GB limit per process isn't really that big an issue, unless you render graphics with a mono-threaded application.
Depends the domain :) We work in satellite images processing here, so 3GB per process is an issue.
What's the Kernel you gots? What's the processing procedure?
John
On Tue, 14 Sep 2010 10:49:28 -0400 JohnS jses27@gmail.com wrote:
On Tue, 2010-09-14 at 16:19 +0200, Laurent Wandrebeck wrote:
On Tue, 14 Sep 2010 16:01:13 +0200 Rudi Ahlers Rudi@SoftDux.com wrote:
Even so, most machines today performs multiple tasks, so 3GB limit per process isn't really that big an issue, unless you render graphics with a mono-threaded application.
Depends the domain :) We work in satellite images processing here, so 3GB per process is an issue.
What's the Kernel you gots? What's the processing procedure?
We're a bit OT here :-) mail me directly if you're interested in some more details.
On 09/14/2010 03:01 PM, Rudi Ahlers wrote:
Even so, most machines today performs multiple tasks, so 3GB limit per process isn't really that big an issue, unless you render graphics with a mono-threaded application.
You are assuming, wrongly, that apps will scale interprocess as they do for inter instances.
For eg: look at mongodb, where using it on 32bit is considered silly,
- KB
On Wed, Sep 15, 2010 at 12:02 PM, Karanbir Singh mail-lists@karan.org wrote:
On 09/14/2010 03:01 PM, Rudi Ahlers wrote:
Even so, most machines today performs multiple tasks, so 3GB limit per process isn't really that big an issue, unless you render graphics with a mono-threaded application.
You are assuming, wrongly, that apps will scale interprocess as they do for inter instances.
For eg: look at mongodb, where using it on 32bit is considered silly,
- KB
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Sure, there are exceptions but my assumptions were on a general scale. So, if this is the case (which I don't think it was with the OP), then 64bit would be better. But in general, 32bit could perform as well.
On 09/15/2010 11:05 AM, Rudi Ahlers wrote:
Sure, there are exceptions but my assumptions were on a general scale. So, if this is the case (which I don't think it was with the OP), then 64bit would be better. But in general, 32bit could perform as well.
No, I dont agree - my point really was that in some corner cases, 32bit might be just as good to have on servers as 64bit, bit on the whole - as a general case, if the option presents itself always go 64bit. You can always chose to run 32bit userland apps ( eg. a firefox.x86_64 does not make much sense, neither does mutt.x86_64 )
- KB
Crystal clear! thank youuuu..!!
Though another Q if possible..
i've done the following:
yum install kernel-pae
vim /etc/grub.conf #outputs the following:
# grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00 # initrd /initrd-version.img #boot=/dev/sda
default=0 #############BOOTING with PAE for additional RAM on 32 bit###### timeout=1 ###speeding things up###### splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu title CentOS (2.6.18-194.11.3.el5PAE) root (hd0,0) kernel /vmlinuz-2.6.18-194.11.3.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet initrd /initrd-2.6.18-194.11.3.el5PAE.img title CentOS-base (2.6.18-92.el5) root (hd0,0) kernel /vmlinuz-2.6.18-92.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet initrd /initrd-2.6.18-92.el5.img
After booting, the system hangs on:
"Memory for crash kernel (0x0 to 0x0) notwithin permissible range" for about 2 to 4 minutes. and then continue booting with the following marked as failed:
1. Mounting HGFS shared 2. VM communication interface 3. VM communication interface socket family 4. blocking file system 5. Virtual printing daemon
Are there related errors to PAE itself, or is it just that VM tools do not support PAE kernel?
thanks
Date: Tue, 14 Sep 2010 15:58:15 +0200 From: l.wandrebeck@gmail.com To: centos@centos.org CC: r_o_l_a_n_d@hotmail.com Subject: Re: [CentOS] Centos Virtual Machine 32 bit with 8 GB ram ?
On Tue, 14 Sep 2010 16:45:50 +0300 Roland RoLaNd r_o_l_a_n_d@hotmail.com wrote:
Thanks for your feedback..
So if i set my VM to 8 GB, each proccess would use a max of 3 GB (even with PAE installed and selected on boot)?
PAE allows a 32 bits host to see more than 4GB of ram. but each process is still limited to ~3gb. To dive a bit more into technical details, PAE is like EMS in DOS time. In EMS, you saw the whole ram, but couldn't allocate more than 64KB per process. With PAE, the same, with a limit of 4GB-OS stuff per process, so it gives something like 3GB. Hope I'm clear.
On Sep 14, 2010, at 10:56 AM, Roland RoLaNd r_o_l_a_n_d@hotmail.com wrote:
Crystal clear! thank youuuu..!!
Though another Q if possible..
i've done the following:
yum install kernel-pae
vim /etc/grub.conf #outputs the following:
# grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00 # initrd /initrd-version.img #boot=/dev/sda
default=0 #############BOOTING with PAE for additional RAM on 32 bit###### timeout=1 ###speeding things up###### splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu title CentOS (2.6.18-194.11.3.el5PAE) root (hd0,0) kernel /vmlinuz-2.6.18-194.11.3.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet initrd /initrd-2.6.18-194.11.3.el5PAE.img title CentOS-base (2.6.18-92.el5) root (hd0,0) kernel /vmlinuz-2.6.18-92.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet initrd /initrd-2.6.18-92.el5.img
After booting, the system hangs on:
"Memory for crash kernel (0x0 to 0x0) notwithin permissible range" for about 2 to 4 minutes. and then continue booting with the following marked as failed:
- Mounting HGFS shared
- VM communication interface
- VM communication interface socket family
- blocking file system
- Virtual printing daemon
Are there related errors to PAE itself, or is it just that VM tools do not support PAE kernel?
You need to recompile your vmware tools for the new PAE kernel.
-Ross
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JohnS -
Karanbir Singh -
Kevin Thorpe -
Laurent Wandrebeck -
Roland RoLaNd -
Ross Walker -
Rudi Ahlers