On 27/08/2012 20:55, Kent Overstreet wrote:

On Mon, Aug 27, 2012 at 12:43 PM, Jonathan Tripathy [off-list ref] wrote:

quoted

On 27/08/2012 20:22, Kent Overstreet wrote:

quoted

echo 1 > /sys/fs/bcache/<uuid>/unregister

echo 1 > /sys/block/bcache0/bcache/stop

Ok, so I managed to recreate everything with a block size of 512 bytes.
However, 2 bad things have happened:

1) In my Linux DomU, my fio randomwrite test have gone from about 28k iops
to about 800 iops. Can this be fixed? changing bs and ba to 512 in the fio
config file didn't hep.

Ouch!

Bet the ssd doesn't like those 512 byte journal writes. I'm going to
have to think about that...

Hi Kent,

Ok, a little good news. I managed to sort out the low IOPS issue. When I 
formatted bcache0 with a 512 block size, I forgot to set the caching 
mode back to writeback. Once I did that, the IOPS were nice and high 
again (circa 26k IOPS). Sorry about the noise regarding that non-issue.

I re-tried the windows setup with writeback enabled for the 512B 
formatted cache. It kernel paniced as per-usual, however for some 
reason, it's kernel panicking upon every boot now, whereas when it was 
formatted with 4k sectors, once the system came back up, it was stable 
(until I tried another windows setup). The debug trace appears to be the 
same as the one I posted to the list (kernel BUG at fs/bio.c:420! 
invalid opcode: 0000 [#1] SMP).

I appreciate your time.

Thanks