On Thu, 18 Feb 2010, Günther wrote:
i was surprised about the seqential write/ rewrite result.
the wd 2 TB drives performs very well only in sequential write of characters
but are horrible bad in blockwise write/ rewrite
the 15k sas drives with ssd read cache performs 20 x better (10MB/s -> 200
MB/s) !!!!
Usually very poor re-write performance is in indication of
insufficient RAM for caching combined with imperfect alignment
between the written block size and the underlying zfs block size.
There is no doubt that an enterprise SAS drive will smoke a
high-capacity SATA "green" drive when it comes to update performance.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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