filesystem checksum problems on AWS EC2 instances

[Colin Percival]

On 2020-09-15 14:30, ericr wrote:
> I'm having disk/filesystem problems creating EC2 instances using
> 12.1-RELEASE (AMI ami-034de978f5d9c9b1b in us-east-1 and AMI
> ami-06d9854b88cba8200 in us-east-2, both from the Marketplace).  I'm using
> t2.large instances.  As a part of the instance creation, the OS gets
> updated from 12.1-RELEASE to 12.1-RELEASE-P9.  THe AMIs use UFS.
> 
> I created instances with a 200GB disk, in both us-east-1 and us-east-2, to
> rule out flakey hardware.  Once the OS starts at first boot, I get cylinder
> checksum errors:
> [...]
> Sep  1 20:50:15 <kern.crit> freebsd kernel: UFS /dev/gpt/rootfs (/)
> cylinder checksum failed: cg 0, cgp: 0x9c14700e != bp: 0x27bfa3d0
> Sep  1 20:50:15 <kern.crit> freebsd syslogd: last message repeated 1 times
> Sep  1 20:50:15 <kern.crit> freebsd kernel: UFS /dev/gpt/rootfs (/)
> cylinder checksum failed: cg 7, cgp: 0x43ed3fa1 != bp: 0xe9b0182e
> 
> and from there on, I get cylinder checksum errors pretty often.

Do you get this if you launch from the non-Marketplace AMIs listed in the
release announcement?
  https://www.freebsd.org/releases/12.1R/announce.html

Theoretically they should be bit-for-bit identical, but I wouldn't put it
past the Marketplace people to have somehow mangled it when they created
their copy of the AMI disk image.

> Also, does anyone have docs on how to create a custom AMI that'll create a
> ZFS root filesystem and install the OS to it?  I can't seem to find AMIs
> for 12.1-RELEASE that use it.

I created some ZFS images for FreeBSD 12.0 last year -- you could launch one
of those and upgrade:
  https://lists.freebsd.org/pipermail/freebsd-cloud/2019-February/000200.html

I've been meaning to create ZFS images for 12.1 but haven't had time (this
isn't my day job, although I do get a few dollars from a Patreon).  At some
point I'll add code to the src tree so this and other "additional flavours"
get built as part of the standard release engineering process.

-- 
Colin Percival
Security Officer Emeritus, FreeBSD | The power to serve
Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid