zfs discuss - Feb 2010 - quick overhead sizing for DDT and L2ARC

Two related questions:

 - given an existing pool with dedup''d data, how can I find the
   current size of the DDT?  I presume some zdb work to find and dump the
   relevant object, but what specifically? 

 - what''s the expansion ratio for the memory overhead of L2ARC entries?
   If I know my DDT can fit on a ssd of size X, that''s good - but how
   much RAM do I need for that ssd to be usable effectively as l2 cache? 

--
Dan.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 194 bytes
Desc: not available
URL:
<http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20100201/acec3050/attachment.bin>