After nine months of not having booted my Windows even once, I think it's time to wipe the Windows related partitions once and for all and claim the space. The problem is I think the way my partitions are structured, it may not be that easy. I am assuming everything other than the two ext4 partitions will have to go. What do you think? r/linux4noobs -
Someone even suggested I nuked the whole thing and started again, which would be the absolute last resort and only when I ran out of space.
EDIT: In the end, having considered all replies, I decided to go with a compromise. I wiped the NTFS partitions and made an ext4 out of the unallocated space. Then, I moved /home to that new, larger partition and if it all continues working for a day or two, I will wipe the old and smaller /home, which is not mounted now anyway, and use it for storage. This allocation will last me for ages until I have to reinstall the OS, at which point I will use the opportunity to tidy things up. I thought this was not the time to break my system moving partitions. There were some hairy moments (eg when a UUID changed quietly and the system failed to start) but overall it was OK.
Thanks to everyone for the help. This thread was very educational and I hope others will find it useful too. As a sidenote, I posted the same question to a much bigger subreddit and I received very few responses and little help. So, the much smaller Lemmy wins hands down!
Swapfile refers to a file at /. As long as you have rootfs there's a place to put that swap file too, so no worries there. Usually there's a separate partition for swap, but that works too.
So, what you need to do is remove sda1 and sda2 windows partitions. That'll leave you ~520GB of unallocated space at the start of the drive. Create a partition there and set it to 'Linux LVM' -type. Then create LVM 'filesystem' on that partition, or more accurately, assign that partition as an LVM physical volume with 'pvcreate'. After that you need to create a volume group with 'vgcreate'. Now you'll have 520GB allocated to LVM. Create new partition for your home with 'lvcreate', use all the space if you like, but at least as big as your current consumption on /home. Then create an filesystem on it and mount it as /mnt/newhome (or whatever).
Log out with your main user and make sure there's no processes running on that user afterwards. Then you can copy data from current home to newhome and unmount the now old home (sda8). Change fstab so that your new home will be mounted on /home (blkid to get UUID and change that to fstab). Mount new home in it's proper place, old home partition will be unmounted at this stage. Verify that everything works.
Now you can change your current sda8, a.k.a. old home, to Linux LVM-type, assign that as LVM physical volume and extend your volume group with vgextend to include the another partition. And now with lvextend you can expand your brand new home directory to that ~850GB total.
But, as I mentioned, make sure that you have your backups in good shape. These steps, if done incorrectly, will destroy your data. That's also why I'm being somewhat vague on the instructions, you'll need to understand what you're doing. There's plenty of information to push you in the right direction, but trust me, it's better for you to take a minute or two and read documentation so that you're actually confident on the steps.
I don't know if LVM acts the same as btrfs, but in order for my root snapshots to work, I couldn't have the swapfile directly in /. It has to be made in /swap/swapfile to work. Just something to be aware of.
It will take some reading but this sounds like a good long-term solution. Perhaps LVM should be the default. And there should be a live USB GUI method that would make the process less scary and safer. Thanks.