[Sheepdog] [PATCH] sheep: unify create_and_write logic for cow and regular object

Christoph Hellwig hch at infradead.org
Wed Nov 16 09:16:43 CET 2011


On Tue, Nov 15, 2011 at 09:31:11PM -0500, tao.peng at emc.com wrote:
> With buffer IO and delayed allocation, I agree it can see the whole
> object. But DIO... do you plan to buffer the whole object in memory
> and send it down in one write system call? With current 4MB objects,
> it seems reasonable. But how about future large objects?

The current code always reads and writes full object size chunks
in store_create_and_write_obj_cow.  If sheepdog switches to partial
object size COWs using fallocate would probably be beneficial.




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