[accrual]

One can certainly stack softraid volumes but I think the FAQ indicates you won't receive support if something goes wrong.

    # bioctl -c 1 -l /dev/sd1a,/dev/sd2a
    softraid0: RAID 1 volume attached as sd3
    # ...
    # bioctl -c C -l /dev/sd3a softraid0
    New passphrase:
    Re-type passphrase:
    softraid0: CRYPTO volume attached as sd4
    # 

I've personally used a setup like this since around OpenBSD 6.0.

[beefhash]

Interesting, I didn't know it worked. A comment on another site by stsp@[1] suggested it doesn't.

https://lobste.rs/s/ljdhug/install_openbsd_on_dedibox_with_f...

[ben_bai]

It does work if you do it manually. The nested softraid will not be assembled at boot. Thus oficially unsupported.