Blogbench RAID benchmarks

Freddie Cash fjwcash at
Thu Jul 21 15:42:21 PDT 2011

On Mon, Jul 18, 2011 at 7:06 PM, Matthew Dillon <dillon at> wrote:
    Ok, well this is interesting.  Basically it comes down to whether we
    want to starve read operations or whether we want to starve write

    The FreeBSD results starve read operations, while the DragonFly results
    starve write operations.  That's the entirety of the difference between
    the two tests.
Would using the disk scheduler's in FBSD/DFly help with this at all?FreeBSD includes a geom_sched class for enabling pluggable disk scheduler's (currently only round-robin algorithm is implemented).
And I believe DFly has dsched? 
    This is all with swapcache turned off.  The only way to test in a
    fair manner with swapcache turned on (with a SSD) is if the FreeBSD
    test used a similar setup w/ZFS.
ZFS includes it's own disk scheduler, so geom_sched wouldn't help in that case.  Would be interesting to see a comparison of HAMMER+swapcache and ZFS+L2ARC, though.
-- Freddie Cashfjwcash at

More information about the Kernel mailing list