[CentOS] xen - 4 concurrent virtual DomU limitation - how to increae this? (centos 5 x86_64)

Urs Rau urs.rau at uk.om.org
Fri Jun 1 21:01:35 UTC 2007


Johnny,

Johnny Tan wrote:
> Urs Rau wrote:
>> Is there a switch or config setting somewhere that would allow me to
>> start up more than the default 4 xen DomU instances?
>>
>> I am finding that the CentOS 5 (x86_64) installation only allows me to
>> start up 4 virtual machines at a time. (It is definetly not a lack of
>> cpu resources, memory or disk space.)
> 
> According to this page:
> http://www.howtoforge.com/perfect_setup_xen3_debian_p5
> 
> You need to add max_loop=N (where N is the number of virtual machines
> you want x 2) to your module line in grub.conf
> 
> But, oddly, I'm using CentOS-5 x86_64, and I have dom0 plus five virtual
> machines running, and I did not change any setting, config file, and I
> don't have max_loop in my grub.conf -- it's just a default install & setup.
> 
> johnn

Thanks, I tried this, but no change. I think this was/is possibly just
related to the limit of number of loopback interfaces the standard
kernel has. And how to increase this. But for me it has no effect on the
number of DomU I can run. I only manage Dom0 + 4 after that it just
hangs on a xm create and when I hit Ctrl-c it comes back with the error
Error: Device creation failed for domain test5.

If I let it try starting the domain for about 1 - 2 minutes it
eventually returns a:

Error: destroyDevice() takes exactly 3 arguments (2 given)

I am attaching my xend.log file for the failed "xm create test5" DomU


My test1 - test5 config files all look as follows:

> # Automatically generated xen config file
> name = "test1"
> builder = "hvm"
> memory = "512"
> boot = "d"
> disk = [ 'file:/xen_dat/test1/test1.img,hda,w', 'file:/xen_img/knoppix/knoppix.iso,ioemu:hdc:cdrom,r' ]
> vif = [ 'type=ioemu, mac=00:16:3e:6f:3e:0d, bridge=xenbr0', ]
> uuid = "2a4d08bd-e7b7-1010-0656-8eb74b692164"
> device_model = "/usr/lib64/xen/bin/qemu-dm"
> kernel = "/usr/lib/xen/boot/hvmloader"
> vnc=1
> vncunused=1
> apic=1
> acpi=1
> pae=1
> vcpus=2
> serial = "pty" # enable serial console
> on_reboot   = 'restart'
> on_crash    = 'restart'


-- 
Urs Rau						

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: xend.log
URL: <http://lists.centos.org/pipermail/centos/attachments/20070601/73c1e4c8/attachment.log>


More information about the CentOS mailing list