Not sure if this should be an offline discussion or not... In response to Mr. Hess' question about netboot image size limits (to which I had no idea of the answer) I e-mailed HPA, the syslinux guy. He responded (posted below) that the only restriction is that the uncompressed + compressed image must fit into system memory.
That said, we could guesstimate what the maximum image size must be for any given system memory space, approximating the formula:
k + z + u(z) < M
where k is the size of the kernel, z is the size of the compressed image, u(z) is the size of the uncompressed image, and M is the system memory.
Taking as an example the compression ratio of the current netboot-initrd image found thusly:
[EMAIL PROTECTED]:/var/ftpd/temp$ gunzip -l ../netboot-initrd.gz compressed uncompressed ratio uncompressed_name 2153194 7462912 71.1% ../netboot-initrd
Or a ratio of about 3.5 to 1 (2.1 * 3.5 = )
If we were to guess that this estimate will hold, the formula becomes:
k + (4.5 * z) < M
The kernel is presently uncompressed (I think???) and weighs in at 730K. By these numbers, systems with the following memory could handle the following initrd.gz sizes:
Round down (M - .800 / 4.5 )
System RAM : Max initrd size 16 MB : 3 MB 32 MB : 6.5 MB 64 MB : 14 MB
Does this make sense or am I way off somewhere?
Erik -------- Original Message -------- Subject: Re: [syslinux] Pxelinux Image size restriction? Date: Wed, 04 Feb 2004 12:08:30 -0800 From: H. Peter Anvin <[EMAIL PROTECTED]>
The only limit is that if the image is compressed, the compressed *plus* the uncompressed image needs to fit in system RAM.
That being said, I have successfully downloaded images over 512 MB in size.
-hpa
Erik Dykema wrote: > Hi- > Is there any size restriction (maximum?) on the size of kernels or > initrd.gz images that pxelinux can fetch over the network and load? > We are currently loading a 730k kernel, and a 2.1 megabyte initrd.gz > image, and everything is working fine. It would be nice, however, to > load larger images that have more stuff on them. Is there any inherent > maximum (other than system ram) to how large of an image we could load? > For example, we could compile more drivers into the initrd.gz image, > and it would become 6 megabytes. Is this too large for pxelinux, the > PXE protocol, or typical hardware to handle? >
Joey Hess wrote:
Erik Dykema wrote:
OK, I think i get it, thanks! I was attempting to install the 'testing' distribution, that must be why it didn't work.
So the 'fix' for this is to get the 2.4.24 kernel into testing.
OR, to build a 'testing' version of d-i.
Yes, I may see about getting the 2.4.24 kernel into testing eventually. However, if you want to test unstable d-i -- and there's no reason to use the unstable netboot images if you don't -- then you should still pick unstable.
As a side note, I have a question regarding why the netboot images need not contain all the necessary drivers? At their current size (2.1 megs) they are too small to fit onto a floppy disk, so they are mostly used by (perhaps here is where I am wrong?) those doing PXE boots (like me)?
On the sizes that we are working with ( 1 - 10 megabytes ) I don't think it would necessarily hurt to include more drivers / modules in the netboot image.
I think there are some netboot image size limits, though I really don't know.
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