Centos 5 guest on CentOS host - slow response

[tcgadmin]

I have a server with the following specs

2xAMD dual core 2.2Ghz, 4GB RAM, 2x72GB raid1 sata disks.

CentOS release 5.3 (Final)
Linux virtual-server 2.6.18-128.1.10.el5 #1 SMP Thu May 7 10:35:59 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
VirtualBox 2.2.4

I have created a 2x centos 5 guest vms with 512MB ram and a 8gb virtual disk each, NAT ip addr.

I ssh into "Linux virtual-server" and then bring up VirtualBox from the commandline. However, the responses for boths vms are very very slow, with the update/frfresh to commands painfully slow, in the order of minutes sometimes. Also, when I select the options from the gui, it will just sit there.

Is there anything that might cause this?

thanks for your time

[fixedwheel]

2xAMD dual core

= 4 core total? (just for the curious)

x86_64 ... vms with 512MB ram

64bit on a 512M machine lacks some sense, or do you want to testcase a machine that normally is bigger?
and 512M feels a little low

NAT ip addr.

I ssh into "Linux virtual-server"

ssh thru NAT? hmm ... - with vbox 2.2.x you could add a "host-only" i/face to reach the virtual machine

Also, when I select the options from the gui, it will just sit there.

the Red Hat type guest kernel running at 1000Hz puts much load on one of the host CPU cores, did you add divider=10 to the kernel parms in /boot/grub/grub.conf?

[tcgadmin]

Hi fixed wheel,

In answer to your questions, and to clarify my setup.

My server (hostname virtual-server) does in effect have "4 x 2.2GHz cpus".

I have trying to consolidate aged linux systems (clock, mail relay, dns). They dont have a desktop running and they run quite happily with 512MB. We already use Xen and I was trying VirtualBox as another alternative. Xen runs very well, with 12GB of RAM and hosts some 20 guest (windows and linux-512mb ram) vms perfectly.

The settings for the vms is to use NAT and they dont have any bridging. When the two linux guests are up, i still have >2GB RAM free

total used free shared buffers cached
Mem: 4046860 1609040 2437820 0 22392 764800
-/+ buffers/cache: 821848 3225012
Swap: 2031608 0 2031608

11:50:01 AM CPU %user %nice %system %iowait %steal %idle
12:00:01 PM all 0.58 9.21 8.30 0.00 0.00 81.90
12:10:01 PM all 0.27 8.98 8.52 0.08 0.00 82.15
12:20:01 PM all 0.39 8.86 8.78 0.24 0.00 81.73
12:30:01 PM all 0.79 4.55 6.64 0.62 0.00 87.40
Average: all 0.51 7.90 8.06 0.23 0.00 83.30

so the system is not stressed.

I have not added the "divider = 10" in /etc/grub.conf. I did not see that in the user manual pdf. What does it do?

Anway, response from the 2 vms is slow, and I dont know why.

There is alot of documentation on using VirtualBox, yet I find it very fragmented. My next question to be posted will do with networking. But I digress.

thanks for your time.

[fixedwheel]

(clock, mail relay, dns). They dont have a desktop running and they run quite happily with 512MB.

ok. Memory isnt your problem but 64bit isnt needed for small 512M machines and wastes some memory compared to 32bit

Xen runs very well, ...

RHEL/Centos xen kernel runs at 250Hz timer clock while default kernel uses 1000Hz

The settings for the vms is to use NAT and they dont have any bridging.

i guess ssh over NAT is one source of your problem. Anyway, if the guest is a server you want to run bridged

I have not added the "divider = 10" in /etc/grub.conf. I did not see that in the user manual pdf. What does it do?

its not a virtualbox feature, its a Red Hat fix for their 1000Hz problem

http://bugs.centos.org/view.php?id=2189
http://wiki.centos.org/Manuals/ReleaseNotes/CentOS5.1