GSoC proposition: multiplatform UFS2 driver

[Richard Yao]

On Mar 14, 2014, at 11:39 AM, Ian Lepore <ian at FreeBSD.org> wrote:

> On Fri, 2014-03-14 at 15:27 +0000, RW wrote:
>> A number of people on the questions list have said that they find
>> UFS+SU to be considerably less robust than the journalled filesystems
>> of other OS's.  
> 
> What I've seen claimed is that UFS+SUJ is less robust.  That's a very
> different thing than UFS+SU.  Journaling was nailed onto the side of UFS
> +SU as an afterthought, and it shows.

This makes sense to me and I am more willing to believe it than the previous claim. I have yet to see a report of a problem involving soft updates that could not have been caused by hardware doing something UFS2 SU was not designed to handle, such as a misdirected write. Sadly, such reports lack the detail needed to distinguish between filesystem bugs and hardware errors. Placing UFS2 SU on a ZFS zvol would prevent such failure modes from happening.