Alexander Motin mav at FreeBSD.org
Fri Jan 20 11:15:47 UTC 2012

On 01/20/12 10:09, Nikolay Denev wrote:
> Another thing I've observed is that active/active probably only makes sense if you are accessing single LUN.
> In my tests where I have 24 LUNS that form 4 vdevs in a single zpool, the highest performance was achieved
> when I split the active paths among the controllers installed in the server importing the pool. (basically "gmultipath rotate $LUN" in rc.local for half of the paths)
> Using active/active in this situation resulted in fluctuating performance.

How big was fluctuation? Between speed of one and all paths?

Several active/active devices without knowledge about each other with 
some probability will send part of requests via the same links, while 
ZFS itself already does some balancing between vdevs.

Alexander Motin

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