Thanks. This is exactly what I was looking for.<br><br>Thank you,<br>Luca<br><br><div class="gmail_quote">On Wed, Dec 16, 2009 at 3:13 AM, Thomas Miletich <span dir="ltr"><<a href="mailto:thomas.miletich@gmail.com">thomas.miletich@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="im">On Wed, Dec 16, 2009 at 11:52 AM, Luca <<a href="mailto:lucarx76@gmail.com">lucarx76@gmail.com</a>> wrote:<br>
> Thanks a lot.<br>
> Something is still not clear to me though. I'm using gPXE on a diskless<br>
> workstation. I use gPXE to download a small ramdisk. Then I use this one to<br>
> do a secondary download of the remaining contents.<br>
> After the download I can do a pivot_root and switch to the new filesystem.<br>
><br>
> Yet the space I have left is 1.5G (since I'm doing first download with gPXE<br>
> and the image can't be bigger than 1.5GB).<br>
<br>
</div>The image you download with gPXE will be much smaller than 1.5GB.<br>
Somewhere around max. 10MB. In this small initramfs you will have all<br>
the modules and programs you need to access the network, and then you<br>
simply have a script to mount a tmpfs or a ramdisk somewhere:<br>
<br>
mount -t tmpfs -o size=4G none /rootfs<br>
<br>
This command will create a 4GB tmpfs and mount it at /rootfs. Now you<br>
can copy the root fs to /rootfs, in any way you like. You could mount<br>
a NFS share and copy it, use sshfs, maybe even rsync.<br>
<br>
It's a good start to take apart your distribution's initramfs( zcat<br>
/boot/initrd.img |cpio -i ) and look at the scripts that usually mount<br>
the HDD or NFS root. You should be able to modify them to copy your<br>
files to your tmpfs and use that as the new rootfs.<br>
<font color="#888888"><br>
Thomas<br>
</font><div><div></div><div class="h5"><br>
> I'm sure I'm missing something, but having everything in RAM, after I<br>
> download a small ramdisk with gPXE, where do I save the content of the<br>
> secondary download (which is going to be around 4G)?<br>
><br>
> Thanks,<br>
> Luca<br>
><br>
> On Fri, Dec 11, 2009 at 10:37 AM, H. Peter Anvin <<a href="mailto:hpa@zytor.com">hpa@zytor.com</a>> wrote:<br>
>><br>
>> On 12/11/2009 07:28 AM, Luca wrote:<br>
>> > Thank you. So gPXE can address 4GB of RAM.<br>
>> ><br>
>> > Then, if I gPXE boot with the following script<br>
>> ><br>
>> > #!gpxe<br>
>> ><br>
>> > kernel <a href="https://192.168.1.189/vmlinuz" target="_blank">https://192.168.1.189/vmlinuz</a> root=/dev/ram0 init=linuxrc<br>
>> > initrd <a href="https://192.168.1.189/ramdisk.img" target="_blank">https://192.168.1.189/ramdisk.img</a><br>
>> > boot<br>
>> ><br>
>> > the ramdisk's size could not exceed 2G (considering gPXE has to download<br>
>> > it and then load it in memory)?<br>
>> ><br>
>><br>
>> Something like that. In practice it is probably closer to 1-1.5 GB.<br>
>><br>
>> You also don't want to actually use a ramdisk -- initramfs is a *lot*<br>
>> more efficient.<br>
>><br>
>> However, realistically you probably don't want to do that. Instead you<br>
>> want to bring up a reasonably small ramdisk that contains the contents<br>
>> needed to do a secondary download of the remaining contents. The<br>
>> reasons are very simple: no need to double buffer, Linux has a *much*<br>
>> more advanced IP stack that gPXE (for, I hope, obvious reasons -- not<br>
>> picking on gPXE here), and no 4 GB limitation.<br>
>><br>
>> As such, you should get much better preformace that way, and when you're<br>
>> talking gigabytes, that matters.<br>
>><br>
>> -hpa<br>
>><br>
>> --<br>
>> H. Peter Anvin, Intel Open Source Technology Center<br>
>> I work for Intel. I don't speak on their behalf.<br>
>><br>
>> _______________________________________________<br>
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>> <a href="http://etherboot.org/mailman/listinfo/gpxe" target="_blank">http://etherboot.org/mailman/listinfo/gpxe</a><br>
><br>
><br>
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><br>
><br>
</div></div></blockquote></div><br>