Considerations multi booting on an SSD

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bigal
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Considerations multi booting on an SSD

Post by bigal »

I am considering upgrading from my current LM 18.3 to 19.2 to see how the upgrade works with my current data and programs. I have a acquired a spare UEFI machine with a 1TB SSD (it is an Acer All-In-One) to test on. So as an experiment, at least initially, I am planning to dual boot Mint 18.3 and 19.2 giving each approximately 25% of the available space. I also have a long term plan to add at least two other OS’s at a later date, Debian 10 and Centos 8 although that might not happen at all. Hence the space restriction. My data files will only be copies so no danger of losing anything important.

This will be my first expedition into using both UEFI using a SSD and it seems to me that there are a couple of important considerations. Firstly partitioning. I have always split Linux up into several partitions. Root, home and particularly /var as logs can fill that one quite quickly if there is a problem. If a segment or small area of a HDD fails there is a chance that software could be used to isolate that part and carry on using the rest giving me time to source a replacement. However, as this machine has a SSD it seems to me that would be a waste of time as I do not see that same action would be possible. If one of the memory locations in a SSD fails then as far as I am aware that is the drive gone. Kerphut!

The other consideration is Swap. 18.3 generates a swap partition. 19.2 uses a swapfile. Bearing in mind my comments about partitions there does not, at least to me, seem to be any reason why I should consider this. Perhaps a swapfile would be better with 18.3. However. It does not appear to matter which course is taken swap means many writes and reads to wherever the swap is. Maybe not so bad on a conventional disk but not necessarily so good on a SSD.

So I am going back to my earlier comment. If my SDD fails I will lose everything. If that IS the case is it actually worth installing and setting up all the OSs’ I am considering? Has anyone any observations please?

rene
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Re: Considerations multi booting on an SSD

Post by rene »

bigal wrote:
Wed Nov 20, 2019 2:10 pm
swap means many writes [ ... ]
It does? I on Linux desktop systems even with 8G never touch swap.

But the main thing, really, is too not concern yourself with the issue. Modern SSDs will last significantly longer on average than magnetic disks do or ever did, and more so the bigger they are. With a 1TB SSD you have a gigantic total write volume to go, for again a desktop system most of the time easily good enough for several decades.

General advise I these days give is to if so desired split of a /data partition to be shared amongst different installs (and possibly with e.g. /data/Documents symlinked into the home directories of said different installs) and nothing else.

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Re: Considerations multi booting on an SSD

Post by pbear »

bigal wrote:
Wed Nov 20, 2019 2:10 pm
The other consideration is Swap. 18.3 generates a swap partition. 19.2 uses a swapfile. Bearing in mind my comments about partitions there does not, at least to me, seem to be any reason why I should consider this. Perhaps a swapfile would be better with 18.3.
I'm aware of no way to configure 18.3 to use a swap file. So, I think you're going to need a swap partition. If you have one, the installer for 19.2 will use it and set up fstab accordingly. Not just theorizing, by the way. I have a multi-boot USB hard drive with both 18.x and 19.x. It's actually an efficient use of space, as one swap partition will serve all four (or whatever) systems, rather than each having its own swap file. I like to put the swap partition early in the partition table, so it doesn't have to be moved later.

Another issue I will mention is that you should decide before you start which system you want to control Grub. To keep it that way, install the bootloader for the secondary systems on their root partitions. If you don't do that, the latest system installed usually ends up controlling Grub. You generally don't want that, especially if the more recent installations are mere test boxes.

Agree with rene about the data partition.

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Re: Considerations multi booting on an SSD

Post by catweazel »

bigal wrote:
Wed Nov 20, 2019 2:10 pm
If one of the memory locations in a SSD fails then as far as I am aware that is the drive gone. Kerphut!
That may have been true sometime last century but it isn't true today. Modern SSDs have a life span that is well in excess of rotating rust devices. In addition, modern SSDs have very smart controllers that will automatically reallocate blocks if a cell goes down. You are concerned over nothing, really.
"There is, ultimately, only one truth -- cogito, ergo sum -- everything else is an assumption." - Me, my swansong.

bigal
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Re: Considerations multi booting on an SSD

Post by bigal »

Thank you all for your comments. I take it that my understanding of SDDs is from the dark ages – a bit like me really.

As I write I am setting up LM 19.2 on the test machine. I have used Gparted on the live DVD (USB drive) to partition up my shiny new system. The first thing I noticed while doing this was that I was unable to set a EFI partition. I was forced to accept this. As soon as I choose fat32 I ended up with a msftdata flag. Once I chose the “Something else” option in the installation program I saw that the pre selected device for the boot loader was /dev/sda. I changed this to /dev/sda1 with the hopeful intention that this will install the boot loader in the first partition. That done I set the remainder as follows
/dev/sda2 /boot 2046 MiB (2 GiB)
/dev/sda3 /var 102400 MiB (3.57 GiB)
/dev/sda4 / (root) 81920 MiB (80 GiB)
/dev/sda5 /home 25600 MiB (25 GiB)
/dev/sda6 /spare 25600 MiB (25 GiB)
For some unknown reason, once I had elected to reboot following installation and having got the message to remove the installation medium, the machine did not automatically restart (gave it 3 minutes) so had to manually power off and boot up. That said all went well. Installed Gparted and all partitions, including /dev/sda1 were exactly as I wanted and that includes the "boot,esp" flag on /dev/sda1 so I am quite pleased.

I have taken note about GRUB pbear. I will have a read up before I go for the second installation. After I will try to add LM 18.3. That promises to be interesting.

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Re: Considerations multi booting on an SSD

Post by jglen490 »

Good that you are set up :D

Just for conversation, why did you partition out /boot and /var rather than leaving them in the / partition? There was a time, long ago, when the recommendation for /boot was to place it close to the MBR. And the log files in /var are pretty well managed out of the box and rarely run away with feasting on disk space.

Of course, it doesn't hurt anything to have as many partitions as you want, just curious!
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bigal
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Re: Considerations multi booting on an SSD

Post by bigal »

Hi jglen490,

Old habits die hard I guess.

I got caught out once with an excess of log files. I had not noticed that a printer driver was running wild. The first thing that happened was that I could not log on. I was going round in circles, entering my user name then password then being asked to do it all again. Used a live DVD to investigate and found my root drive 100% filled. Sorted out the logs which reduced the used capacity to a more manageable size which in turn allowed me to log in and sort out the driver. I have always split everything up ever since.

Still trying to understand why pbear has advised keeping GRUB and the bootloader in additional system’s root partitions. Too late tonight. More time for reading tomorrow.

Edit. PS added Love your signature.

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catweazel
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Re: Considerations multi booting on an SSD

Post by catweazel »

bigal wrote:
Thu Nov 21, 2019 5:10 pm
I got caught out once with an excess of log files.
Now timeshift catches an awful lot of people out. New users seem to want to let timeshift store its archives under root, which, I think, is a serious shortcoming of the software.
"There is, ultimately, only one truth -- cogito, ergo sum -- everything else is an assumption." - Me, my swansong.

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Re: Considerations multi booting on an SSD

Post by jglen490 »

Oh, there are still bruises healing from that conversation :lol: :!:
I feel more like I do than I did when I got here.
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Re: Considerations multi booting on an SSD

Post by Sgthawker »

Hello bigal,

Well to start with you don't need /boot for a UEFI system, so that is wasted space. The esp will handle it at about 500 mb max size.

If you are installing Ubuntu based distros you can install from the terminal with ubiquity -b to install sans grub leaving your first install in control of it. You can select to not install grub in fedora, so you should be able to in centos as well, though I am not sure. Debian also has a method of installing sans grub. If all else fails you can reinstall grub with the distro booted that you want to be in control.

I have had 10 distros on a laptop with an SSD and UEFI whilst sharing the /data partition mentioned above symlinked to each distro for ease. It worked very well. I also used that system to distro hop and don't even remember how many installs I have performed with no degradation noted.

I created a swap partition and set it in each install by default with no issues, but, I do not hibernate, which can be an issue in multiboot.
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Re: Considerations multi booting on an SSD

Post by pbear »

bigal wrote:
Thu Nov 21, 2019 12:31 pm
As soon as I choose fat32 I ended up with a msftdata flag.
For future reference, all you had to do was right-click the partition and select Manage Flags. Once you tick boot, esp gets ticked automatically also.
Still trying to understand why pbear has advised keeping GRUB and the bootloader in additional system’s root partitions.
Main thing to understand is that, if you don't do something, each new installation will take control of Grub. How to prevent or fix that is a matter of preference. I tried installing secondary systems without a bootloader as Sgthawker suggests. Boot became noisy (loss of quiet splash) and I had shutdown issues that probably only arise when booting from USB drive, which is where my multi-boot test box resides. Annoyed me enough that I redid the installations after about three of 'em. Have done it with secondary bootloaders on root ever since. YMMV.

Nov 22nd: A few points edited for clarity.

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Re: Considerations multi booting on an SSD

Post by bigal »

pbear wrote:
Fri Nov 22, 2019 12:41 am

Main thing to understand is that, if you don't do something, each new installation will take control of Grub. How to prevent or fix that is a matter of preference. I tried installing secondary systems without a bootloader as Sgthawker suggests. Boot became noisy (loss of quiet splash) and I had shutdown issues that probably only arise when booting from USB drive, which is where my multi-boot test box resides. Annoyed me enough that I redid the installations after about three of 'em. Have done it with secondary bootloaders on root ever since. YMMV.

Nov 22nd: A few points edited for clarity.
Once the subsequent installation is added can't you just edit GRUB to tell it which OS you want it to default to?

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Re: Considerations multi booting on an SSD

Post by pbear »

Which system boots by default is the least of your worries, but yes, you can set default boot no matter which system controls Grub.

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Re: Considerations multi booting on an SSD

Post by bigal »

Hmm. In which case I am not sure what you mean by " ... which system controls Grub"

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Re: Considerations multi booting on an SSD

Post by rene »

The Grub bootloader reads /boot/grub/grub.cfg at boot --- but which /boot/grub/grub.cfg is what pbear refers to. Answer is the /boot/grub/grub.cfg of whichever distribution last ran grub-install <device> which, unless you arrange otherwise or fix things after the fact, is the last distribution that gets installed.

bigal
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Re: Considerations multi booting on an SSD

Post by bigal »

Thank you rene. That is what I would expect, but I don't see that as a problem. Probably just my ignorance. Can it cause other conflicts then, and if so how please?.

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Re: Considerations multi booting on an SSD

Post by pbear »

FWIW, I do it as described above for several reasons. First, it's easier to remember which system is primary if it doesn't change every time you install a new test box. Second, if you delete the primary system, you have to reinstall Grub somewhere else. Third, there's no advantage to having Grub passed around. On the contrary, if you're going to want the same system to be default boot, you're just making more work for yourself.

An important point I'm not sure you understand is that only one Grub actually works. So, for example, when you update kernels in the secondary systems, those updates don't take effect until you run update-grub in the primary system.

Anyhoo, no skin off my nose which way you do it. Good luck.

bigal
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Re: Considerations multi booting on an SSD

Post by bigal »

Thank you for the explanation pbear. I had not given any of those facts any thought at all.

I am still reading through this post

Code: Select all

https://forums.linuxmint.com/viewtopic.php?f=46&t=30623
as well as the links it contains. That is the beauty of this forum, the information is there – but it can take ages to find it. That said, when someone is kind enough to point something out to me I am truly grateful.

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Re: Considerations multi booting on an SSD

Post by bigal »

The heading I chose for this post was “Considerations multi booting on an SSD” I have discovered that one of the considerations is that I cannot use Firefox in the way that I have always done. Please see my post at

Code: Select all

https://forums.linuxmint.com/viewtopic.php?f=47&t=305969&p=1719121#p1719121
That post refers exclusively to Firefox but I am of a mind that Thunderbird would react in exactly the same way. At the moment I am thinking that multi booting will not be worth the hassle. But, of course, I don’t actually know. I have to bear in mind that there will be a time when support for 18.3 expires at which point, if there are no dramatic changes, I will not be left with much of a choice.

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Re: Considerations multi booting on an SSD

Post by pbear »

bigal wrote:
Sun Nov 24, 2019 2:44 am
I am still reading through this post viewtopic.php?f=46&t=30623 as well as the links it contains.
By all accounts, Fred was a genius. (Probably still is, just no longer active here.) That thread is ten years old. Should not be relied on for anything.

As for the Firefox problem discussed in your other thread, ISTM there are several solutions, of which the simplest would be to let go of the notion that you can share profiles.

By the way, please don't use code boxes for links. Just paste in the link and the bulletin board software will make it clickable.

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