Another solution that seems to work with multiple Linux distro's is only allow the first one installed to install Grub to the drive (/dev/sda).
For any subsequent distro's set Grub's install location to that distro's own partition.
Then only the Grub installed on /dev/sda is used at bootup & the others don't overwrite it when their systems are installed or cause conflicts etc..
Not sure if that idea is good, bad, ugly or frowned upon but I find it works without any problems.
I've just finished setting up a triple boot with LL 3.0, Mint & LXLE, each with their own swap, LL 3.0 being the first intalled, but it doesn't necessarily have to be first, the important thing is only let Grub get installed to /dev/sda by the first OS installed.
I did this:
Drive is /dev/sda where Grub was installed when installing LL 3.0.
/dev/sda1 is LL 3.0, set as primary, rest are set as logical.
/dev/sda5 is LL 3.0's swap.
/devsda6 is LXLE, LXLE's Grub also installed there.
/dev/sda7 is LXLE's swap.
/dev/sda8 is Mint, Mint's Grub also installed there.
/dev/sda9 is Mint's swap.
After that the system will only boot into LL 3.0 as the other Grubs are effectively nullified because of where they're installed to.
So to get around that easily I installed Grub Customizer, made sure it was set to look for other operating systems & it was set to show the menu, set the timer for 30 seconds (before it boots into the default entry which is LL 3.0) saved the configuration & now when rebooting or starting up I get the Grub menu with a choice of either LL 3.0, LXLE or Mint, select one hit enter, job done, no hassles no conflicts.
Any more operating systems get added install their Grub to their partitions, Grub Customizer has to be used again & the configuration saved so the newer system shows in the menu at bootup.
As I mentioned I'm not sure if that idea is frowned upon or not but it works for me, is fairly simple to do & works well without any hassles.
I've only done this with multiple Linux distro's, several times without any hassles, no Windows OS's in the mix anywhere so I have no idea if it would work properly with a Windows system.
The installers will also probably try to refomat any existing swap so I change the existing swap partitions to 'Do not use' in the partition editor of each before writing the changes to disk, if I didn't I found the swap would be always set to off when running the other systems again.
For any subsequent distro's set Grub's install location to that distro's own partition.
Then only the Grub installed on /dev/sda is used at bootup & the others don't overwrite it when their systems are installed or cause conflicts etc..
Not sure if that idea is good, bad, ugly or frowned upon but I find it works without any problems.
I've just finished setting up a triple boot with LL 3.0, Mint & LXLE, each with their own swap, LL 3.0 being the first intalled, but it doesn't necessarily have to be first, the important thing is only let Grub get installed to /dev/sda by the first OS installed.
I did this:
Drive is /dev/sda where Grub was installed when installing LL 3.0.
/dev/sda1 is LL 3.0, set as primary, rest are set as logical.
/dev/sda5 is LL 3.0's swap.
/devsda6 is LXLE, LXLE's Grub also installed there.
/dev/sda7 is LXLE's swap.
/dev/sda8 is Mint, Mint's Grub also installed there.
/dev/sda9 is Mint's swap.
After that the system will only boot into LL 3.0 as the other Grubs are effectively nullified because of where they're installed to.
So to get around that easily I installed Grub Customizer, made sure it was set to look for other operating systems & it was set to show the menu, set the timer for 30 seconds (before it boots into the default entry which is LL 3.0) saved the configuration & now when rebooting or starting up I get the Grub menu with a choice of either LL 3.0, LXLE or Mint, select one hit enter, job done, no hassles no conflicts.
Any more operating systems get added install their Grub to their partitions, Grub Customizer has to be used again & the configuration saved so the newer system shows in the menu at bootup.
As I mentioned I'm not sure if that idea is frowned upon or not but it works for me, is fairly simple to do & works well without any hassles.
I've only done this with multiple Linux distro's, several times without any hassles, no Windows OS's in the mix anywhere so I have no idea if it would work properly with a Windows system.
The installers will also probably try to refomat any existing swap so I change the existing swap partitions to 'Do not use' in the partition editor of each before writing the changes to disk, if I didn't I found the swap would be always set to off when running the other systems again.