Because I don't want "why?" as response, I will start with the background.
I wanted to make a software RAID-0 of 2 disks since they are quite slow and small in size because they are very old. So I want to spare minimum amount of space for /boot partition at the beginning of the drive. I did search and found that Linux in general uses between 128mb to 2.5gb and for Ubuntu about 250mb to 1gb. But since I know what I'm installing (Ubuntu 18.04.2 x64 alternate) I wanted to know a number that is little bit more precise than 250mb to 1gb.
So to the question: What is minimum required size of /boot partition for Ubuntu 18.04.2?
111 Answer
What is minimum required size of /boot partition for Ubuntu 18.04.2?
Answer: 732.00 MiB. I just did an Ubuntu 20.04 install on a completely empty disk and I let it do all the partitioning stuff. I chose the options for "LVM" and "encrypted partition" or whatever, then looked at gparted to see what partition scheme it produced. Here's what I saw on my 512GiB drive:
Partition Name File System Mount Point Size Used Unused Flags
--------- ---- ----------- ----------- ---------- ---------- ---------- -----
/dev/sda1 EFI System Partition fat32 /target/boot/efi 512.00 MiB 1.02 MiB 510.98 MiB boot,esp
/dev/sda2 (none) ext4 /target/boot 732.00 MiB 47.66 MiB 684.34 MiB (none)
/dev/sda3 (none) [Encrypted] lvm2 pv vgubuntu 475.72 GiB 475.72 GiB 0.00 B (none)So, it gave the /target/boot partition 732.00 MiB. If I was doing this manually, I'd just give it 1 GiB and call it good.
Update: I've posted this on ServerFault too: What is the recommended size for a Linux /boot partition?
