New ZFSv28 patchset for 8-STABLE

Bob Friesenhahn bfriesen at simple.dallas.tx.us
Mon Jan 10 18:18:34 UTC 2011


On Mon, 10 Jan 2011, Attila Nagy wrote:
>
> Having this choice is good, and in this case enabling this makes sense for 
> me. I don't know any reasons about why you wouldn't use all of your L2ARC 
> space (apart from sparing the quickly wearing out flash space and move disk 
> heads instead), but I'm sure Brendan made this choice with a good reason.
> If you get an answer, please tell us. :)

Consider that your L2ARC device might be bandwidth limited to 
100-240MB/second while your main storage is capable of 1000MB or 
2000MB second sequential data transfer.  This a good reason to not 
simply put all data (which does not fit in normal ARC) into L2ARC. 
ARC is supposed to be adaptive ...

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/


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