ZFS: WriteBack versus SSD-ZIL

[Richard Pieri]

On Mar 5, 2010, at 8:36 AM, Edward Ned Harvey wrote:
> 
> I have a hypothesis.  I think the best configuration will be to use a PERC,
> with WriteBack enabled on all the spindle hard drives, but include an SSD
> for ZIL, and set the PERC for WriteThrough on the SSD.  This has yet to be
> proven or disproven.

Best for performance if you never fill the SSD.  If you do fill it then things get ugly.  How ugly depends on how you have the SSD-to-Disk flush configured.

--Rich P.