The real issue is not the size of the iso, but using tftp protocol toOn 11/20/2011 05:21 PM, Francesco Frassinelli wrote:
> Hi all,
> I need to boot a livecd on some hard disk less clients. I tried to use
> livecd-iso-to-pxe, but in my case it unacceptable to load the whole
> iso into initrd (the iso is not small).
> I made a custom livecd adding dracut-network package, I mounted
> squashfs/root image, exported with nfs, and I've tried to boot the
> clients with root=nfs:192.168.1.50:/home/frafra/root/ selinux=0, but
> Fedora gives me many errors because it can't write on it.
> I found this old thread
> http://comments.gmane.org/gmane.linux.redhat.fedora.livecd/4261 but it
> doesn't work for me.
> Is there a way to get a livecd behaviour with this nfs directory? Or
> can I combine the isolinux.cfg livecd options with
> root=nfs:192.168.1.50:/home/frafra/ (where it could found the iso or
> the mounted iso)?
> I'm using dnsmasq with its internal tftp server, which gives vmlinuz0
> and initrd0.img (copied from livecd), pxelinux.0 and a configuration
> file with the above root=nfs:[...] selinux=0 options.
load it.
TFTP needs to ack each segment before the next is sent, thus severely
throttling throughput.
On a 100BT interface, tfpt maxes out at about 2MB/sec.
On a 1000BT interface, tftp maxes out at about 15MB/sec
I would propose using a different method for identifying the initrd to
dracut during the PXE boot process.
Current:
KERNEL /images/centos_server_kvm/vmlinuz0
APPEND rootflags=loop initrd=/images/centos_server_kvm/initrd0.img
root=live:/centos_server_kvm.iso rootfstype=auto ro liveimg quiet rhgb
rd.luks=0 rd.md=0 rd.dm=0
Proposed:
KERNEL /images/centos_server_kvm/vmlinuz0
APPEND rootflags=loop
initrd=http://mymirror.mycompany.com/images/centos_server_kvm/initrd0.img root=live:/centos_server_kvm.iso
rootfstype=auto ro liveimg quiet rhgb rd.luks=0 rd.md=0 rd.dm=0
That would literally shave minutes off of boot times by increasing
throughput of the large image by a factor of 10 or more.
This is somewhat of a paradox issue, because many of the network and
protocol drivers are within the initrd images. Surely there must be a
way ...