fc9 and rhel5 shared /boot and lvm coexistence

[Chris Snook]

Chris Snook wrote:
> John Priddy wrote:
>> So I would like to have rhel5 and fc9 coexisting on the same physical 
>> disk.  My questions/concerns are as follows:
>>
>> 1.  Is there any issue with sharing the /boot mountpoint/partition 
>> between both?
>>
>> 2.  I haven't worked a lot with shuffling around VGs, but how about 
>> sharing lvm volumes in general?  If I create some generic (not root) 
>> lvm volume and lay down an ext3 filesystem in FC9 should I expect any 
>> problems when trying to mount the same in RHEL5?  Is there any issue I 
>> should be aware of regarding differing versions of lvm?  Is it worth 
>> while/possible to share the swap volume -- lets say I put the computer 
>> into hibernate in FC9, then later on I boot up into RHEL5, whats the 
>> worst thats going to happen?
>>
>> 3.  Anyone else out there doing something like this that has any 
>> additional advice?
>>
>> Thanks
>>
>> John
>>
> 
> It works, but it can be a pain in the ass.  Personally, I prefer to have 
> separate /boot partitions, and chainload them from the first one, which 
> holds the oldest distro.  That way, if a new distro adds features that 
> are incompatible with an older bootloader, each OS is still being loaded 
> by its own bootloader.  The only catch is that you have to be careful 
> and make sure that when installing the non-primary distros that you put 
> the bootloader on the /boot partition, not on the MBR.
> 
> Anaconda makes it very easy to create a chainload entry pointing to 
> another partition.  I usually leave a few GB of space free so I can 
> create extra /boot partitions at will, and put all the rest in LVM.
> 
> -- Chris
> 

I realized I didn't really directly answer questions #1 and #2.

1)	I can't think of any specifically for RHEL5/F9, but I've had problems sharing 
/boot between distros in the past.  The nastiest one is dual-booting x86_32 and 
x86_64 when the distros don't include the arch in the kernel and initrd 
filenames.  Might as well set yourself up for chainloading now, so you don't 
have to worry about these sorts of problems if you decide to add a distro that 
has such a problem.

2)	Anything needed to boot the system should probably not be shared.  Sharing 
/home is fine and even encouraged.  The system will actually set itself up to 
share swap automatically unless you tell it not to, which could cause 
hibernation problems.  You can rectify that by forcing each distro to use a 
distinct swap partition, and check /etc/fstab post-install to make sure it 
didn't auto-add the other one.  If you're not doing hibernation, sharing swap is 
perfectly fine.

As for LVM versions, anything running a 2.6 kernel will use LVM2 and be 
compatible, so you won't have problems unless you try to share with a very old 
distro.  Just put it all in one VG for simplicity.

-- Chris