Switchover to CAM ATA?

[Dag-Erling Smørgrav]

Alexander Motin <mav at FreeBSD.org> writes:
> Dag-Erling Smørgrav <des at des.no> writes:
> > Most pseudo-raid kit has nifty features like checksum offloading,
> > composite writes etc. which can improve performance considerably.  You
> > can't access those from GEOM.
> Have you ever seen them documented?

ISTR I got the info from sos@ at some point.  I have several Promise
cards lying around and was working onm RAID5 offloading, but I stopped
when ZFS became usable.

> Does the need to specifically handle dozens of incompatible
> implementations with limited resources worth those (probably not
> major) benefits?

The details probably vary from controller to controller, but the
capabilities are pretty much the same: perform the same write operation
to several disks at once, split a write operation across several disks,
compute and write parity.

IIRC, composite writes are already supported but not used.

DES
-- 
Dag-Erling Smørgrav - des at des.no