zfs discuss - Jun 2010 - Gonna be stupid here...

But it''s early (for me), and I can''t remember the answer here.

I''m sizing an Oracle database appliance.   I''d like to get one
of the
F20 96GB flash accellerators to play with, but I can''t imagine
I''d be
using the whole thing for ZIL.  The DB is likely to be a couple TB in size.

Couple of questions:

(a) since everything is going to be zvols, and I''m going to be doing 
lots of sync writes to them, I''m thinking that allocating around a
dozen
GB of the F20''s flash would be useful.  :-)

(b) can zvols still make use of an L2ARC device for their pool?  I''m 
assuming so, since it''s both block and metadata that get stored there. 
I''m considering adding a couple of very large SSDs to I might be able
to
cache most of my DB in the L2ARC, if that works.


-- 
Erik Trimble
Java System Support
Mailstop:  usca22-123
Phone:  x17195
Santa Clara, CA

On 24/06/2010 17:49, Erik Trimble wrote:
> But it''s early (for me), and I can''t remember the answer
here.
>
> I''m sizing an Oracle database appliance. I''d like to get
one of the F20
> 96GB flash accellerators to play with, but I can''t imagine
I''d be using
> the whole thing for ZIL. The DB is likely to be a couple TB in size.
>
> Couple of questions:
>
> (a) since everything is going to be zvols, and I''m going to be
doing
> lots of sync writes to them, I''m thinking that allocating around a
dozen
> GB of the F20''s flash would be useful. :-)
>
> (b) can zvols still make use of an L2ARC device for their pool?
I''m
> assuming so, since it''s both block and metadata that get stored
there.
> I''m considering adding a couple of very large SSDs to I might be
able to
> cache most of my DB in the L2ARC, if that works.
Yes, the level that the L2ARC works at doesn''t care if the dataset is 
filesystem or ZVOL.

-- 
Darren J Moffat