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#1
Posted 01 December 2012 - 01:34 AM
#2
Posted 01 December 2012 - 02:35 AM
Not really, but what are you booting, exactly?Is there a way to limit the "visible" with Syslinux? I can do that with lilo and Grub so that my OS' see as much RAM as I choose.
#3
Posted 01 December 2012 - 03:04 AM
#4
Posted 01 December 2012 - 03:34 AM
I assume that you are using Syslinux' mboot.c32 to boot ESXi 5.1. mboot.c32 does not take a command-line parameter modify the E820 memory map, as far as I know. Doing so would involve installing a hook before Syslinux passes control to the kernel.ESXi 5.1, it will not boot if you have over 32GB of RAM. And this is a leased server in a remote DC so no way of physically removing the RAM either. Lilo and Grub can fool the ESXi kernel no problem with conf file setting and I was wondering if Syslinux (the ESXi bootloader) has this capability or else I will have to use another bootloader.
Just out of curiosity, what LILO and/or GRUB invocations are you using to limit memory? I asked my original question because some OS's will allow you to control the memory perspective via a kernel command-line parameter. If that's how you're doing it with LILO and GRUB, then it should be possible with mboot.c32.
The only exception to this would be if it's not really a kernel command-line parameter, but merely looks like one. (For example, if the command-line parameter is an instruction to LILO or GRUB, rather than to the kernel.)
#5
Posted 01 December 2012 - 04:13 AM
# these options don't get added to recovery boot entry
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
# these options get added to both standard and recovery boot entries
GRUB_CMDLINE_LINUX="var1 var2 mem=1024m"
And Debian sees only 1024m
#6
Posted 01 December 2012 - 04:32 AM
That looks like it could go in an mboot.c32 invocation. Try placing those after the kernel module's name and before the next set of hyphens, or share your Syslinux config-file and we can think about the change, together.On a Debian 7 system we added this to the grub.conf:
# these options don't get added to recovery boot entry
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
# these options get added to both standard and recovery boot entries
GRUB_CMDLINE_LINUX="var1 var2 mem=1024m"
And Debian sees only 1024m
#7
Posted 01 December 2012 - 05:19 AM
default safeboot.c32
nohalt 1
#8
Posted 01 December 2012 - 05:51 AM
Unfortunately, this is a custom ComBoot32 module; not one that comes with Syslinux. We will have to find the source code in order to see what it does. If it invokes mboot.c32 somehow (or is a modified version of it), then perhaps we'll find out what needs to happen in order to pass the mem= option to the ESXi multiboot kernel. Let's see...Here you go:
default safeboot.c32
nohalt 1
---EDIT--- As usual, it's non-trivial to find the source code from a vendor that is using open source software with their product. I've e-mailed the mailing-list to find out if anyone knows where to find it. However, since there don't seem to be many options in that file, is there perhaps another config-file that safeboot.c32 might be using for further options? You might gain a clue by examining the output of strings safeboot.c32. I came across web-pages mentioning a boot.cfg file, for instance...
#9
Posted 01 December 2012 - 10:21 AM
#10
Posted 01 December 2012 - 12:24 PM
That's exactly the idea of OPEN SOURCE, you decompile the binary!Maybe it could be decompiled and examined for possible arguments. Files alongside with it are ldlinux.sys mboot.c32 and syslinux.cfg
![:w00t:](https://reboot.pro/public/style_emoticons/default/w00t.gif)
Are we talking of VMware ESXi?
There are sources for v 5.1 (though not linked to from the "main" product page
![:dubbio:](https://reboot.pro/public/style_emoticons/default/dubbio.gif)
https://my.vmware.co...5_1#open_source
https://my.vmware.co...S&productId=285
https://my.vmware.co...S&productId=268
https://my.vmware.co...S&productId=284
![:cheers:](https://reboot.pro/public/style_emoticons/default/cheers.gif)
Wonko
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