Filesystem corruption and bad perfomance with SRCS16 and PAE ( raid 5 2TB)

John Baldwin jhb at
Thu Nov 15 07:41:50 PST 2007

On Wednesday 07 February 2007 04:58:17 am Daniel O'Connor wrote:
> On Wednesday 07 February 2007 19:23, Artem Kuchin wrote:
> > FreeBSD/amd64 is a very young platform on FreeBSD. While the core FreeBSD
> > kernel and base system components are generally fairly robust, there are
> > likely to still be rough edges, particularly with third party packages."
> >
> > scares me. Do you really think it is better than PAE?
> PAE is quite young as well, I think it was committed to the tree around March 
> 2003. The earliest AMD64 commit I could find was May 2003 although repo 
> copying makes it confusing..
> I think you'll find the list of drivers incompatible with PAE to be much 
> longer with amd64.

Err, amd64 and PAE are the same problem for drivers (dealing with 64-bit
physical addresses for DMA which can require bounce buffering if your
hardware only supports 32-bit physical addresses).  The fix is to use
the bus_dma abstraction in the driver instead of directly using vtophys()
and a driver needs that fix for both PAE and amd64.  amr(4) should work
fine with both PAE and amd64 with > 4GB of RAM.

John Baldwin

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