EFI partition size

[Michael Grimm]

Hi,

I used to set the EFI partition size to 100 M for the past years.

Today I tested the installer on Hetzner's FreeBSD 15.0-RELEASE image at https://www.hetzner.com/cloud/ and found the installer setting this EFI partition size to be about 260 M.

Well disk size is cheap nowadays, but what would be a reasonable partition size for the next years to come?

Thanks and regards,
Michael

[Frank Leonhardt]

Hi Michael,

FreeBSD used to use a relatively small EFI partition: <1Mb. I've noticed it getting larger. The only reason I can think of is so you can store more stuff on it like firmware update tools and alternative bootloaders (for other operating systems) - they've got to go somewhere outside the OS partitions.

It's a good question. My guess is you don't need nearly as much if you're using the disk for nothing but FreeBSD. There's still time for someone who knows the inside story to answer.

You can look at the EFI partition easily enough, being FAT. There's usually about 1-2Mb in there. I'd say allow 4Mb to be safe. Maybe 8Mb to be extremely safe. The worst that can happen is you need to install more bootloaders and have to expand it, which would be a PITA but you'd also need space on the disk for more operating systems and you're probably setting the whole drive up for FreeBSD anyway.

Regards, Frank.

[Michael Sierchio]

Frank is entirely correct.  I run my ARM64 EC2 instances with an 8M EFI boot partition.  It's overkill, but it allows for flexibility if I want to include silly things later on.  

/boot/efi/efi/boot/BOOTaa64.efi : 393216 bytes

1. Name: nda0p1

   Mediasize: 8388608 (8.0M)

   Sectorsize: 512

   Stripesize: 4096

   Stripeoffset: 0

   Mode: r1w1e1

   efimedia: HD(1,GPT,d012c8df-f675-11ee-8a96-7fb2188a5702,0x28,0x4000)

   rawuuid: d012c8df-f675-11ee-8a96-7fb2188a5702

   rawtype: c12a7328-f81f-11d2-ba4b-00a0c93ec93b

   label: boot

   length: 8388608

   offset: 20480

   type: efi

   index: 1

   end: 16423

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