Re: [isar-cip-core][RFC][PATCH 10/10] Enable A/B snapshot for /var on x86 and qemu-arm64

Jan Kiszka
2025-01-30T15:38:30Z

On 30.01.25 15:06, Moessbauer, Felix (FT RPD CED OES-DE) wrote:
> On Thu, 2025-01-30 at 10:39 +0100, Jan Kiszka wrote:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> Other targets still need testing, some even kernel config tuning.
>
> Hi,
>
> do we have a target that uses docker / podman? The containers are
> usually stored on /var and this is not necessarily compatible with
> BTRFS OOTB. In general, docker does not play nicely with a COW
> filesystem. That's one of the reasons the docker-btrfs driver was
> invented. However, I'm unsure how that works together with our A/B
> logic.
>
> For details, please also see
> https://docs.docker.com/engine/storage/drivers/btrfs-driver/
>

Yes, there is more to think about when it comes to production use. E.g.,
you may also not want to rollback your logs in /var/log on failed
updates. That pattern we may address later on by creating a carveout
from var on a separate partition again.

In the end, this here is just a proposal that may need further tuning
when further requirements need to be fulfilled.

Jan

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