[dm-devel] Performance question when blocks in thin-pool are assume zeroed

Joe Thornber thornber at redhat.com
Tue May 13 13:59:59 UTC 2014

Hi Wayne,

I see you're using a 3.6 kernel.  Could I trouble you to try with 3.14
please?  Mike Snitzer wrote a very nice patch recently that implements
a separate deferred list for each thin device, and then sorts
individual bios using a btree.


- Joe

On Mon, May 12, 2014 at 05:03:39PM +0800, Wayne Chou wrote:
> Hello,
> I am using 4 drives to construct a RAID5 and build a thin
> volume on it. To get better performance, I use '-Zn' option
> in 'lvcreate' to make the thin pool assume all blocks are
> already zeroed.  The chunk size in RAID5 and thin-pool are
> both 512KB and the stripe_cache_size=4096 on RAID5.

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