[ipxe-devel] Size limit in iPXE

[Michael Brown]

On 16/03/16 17:59, Pedro Goncalves wrote:
> We are trying to use iPXE to boot a firmware update ISO provided by Dell
> to update our Dell Poweredge servers, but iPXE fails to fetch the iso
> with the error “Error: No space left on
> device”(http://ipxe.org/err/341820). The size of the iso is approx. 2GB.
> So we wanted to ask you if there is a size limit hardcoded somewhere. If
> not, why are getting this error message? Our server has 128GB of RAM, so
> that can’t be the issue.

How are you trying to boot this ISO?

Downloads are placed in the 32-bit address space (i.e. below 4GB).  It 
is very plausible that a large chunk of this address space is allocated 
for PCI BARs, and so you may have only ~2GB of actual RAM within this 
address space.

You can try SAN-booting your ISO instead, which will not require it to 
first be downloaded into RAM.  For example:

   sanboot http//192.168.0.1/boot/dell.iso

However, most ISOs are not amenable to network booting anyway.  You 
generally have to unpack the contents of the ISO, expose those contents 
via a web server, use iPXE to boot the kernel+initrd directly from the 
web server, and pass in command line arguments so that the initrd can 
locate the web server to load the remainder.

Michael