RELENG_7 heavy disk = system crawls

[grarpamp]

> cards aren't going to help with zfs.

No, but for geli hifn(4) crypto(4)/(9), geli(8) might work
if aes-cbc is indeed the mode geli uses. See the source I guess.

> Does anyone make a disk controller with crypto built in?

Yes. There are trays and cable dongles and things that do aes/des.
And some drives are coming out with it in firmware. Does anyone
like the cost, closed-source, and trust model of such hardware?

> atacontrol

I'm partly up against this because some failing drives are negotiating
lower speeds for themselves. Never thought of is as a test tool though.

> Pata doesn't do error detection on the control info

ZFS handles that and informs user about silent corruption. Precisely
because of the chained checksums. It's quite addicting.
http://www.opensolaris.org/os/community/zfs/

Your little to no overhead for ffs sounds right as always.