zfs discuss - Jul 2010 - question re how data is stored in L2ARC cache

Hello,

I''m using Nexenta and am impressed by allof the OpenSolaris, ZFS and 
Nexenta parts, thank you for feeing us of the RAID hole.

Having created zvols in a pool (6 mirror sets, 2 SSDs for L2ARC), with 
compression turned on, I am now realising that the data stored in the 
L2ARC SSD is the ''raw'', not the ''compressed''
form (just finished reading
http://blogs.sun.com/dap/entry/zfs_compression).

Does anyone know if it would be technically feasible (one day) to cache 
the compressed data there ?

For data (like databases) that compresses quite well (e.g. 3.5x), if the 
compressed form is stored, a 100GB L2ARC cache essentially would hold 
350GB, which would be a big win.

If this is potentially in the pipeline great... Otherwise, I''ll go back
to the SSD shop...

Many thanks again

Frederic

-- 
Frederic Vander Elst
Group Head of IT
The pH Group
Direct Line: 020 7598 0320
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