[OmniOS-discuss] re-tune round-robin reading from a mirror

[Dan McDonald]

> On Jul 15, 2015, at 11:45 AM, Schweiss, Chip <chip at innovates.com> wrote:
> 
> This is a very interesting idea.  It could allow for the creation of a scratch pool with great ROI.   I have a particular need for an extremely high read rate pool for data analysis that will leverage the fattest read optimized SSDs I can get for the dollar.  I was considering this to be raidz1, but if mirroring with disks would work this way, it could be even better bang for the buck. 
> 
> Did you ever do any actual testing with this type of setup?  I'd love to see some real world performance data.

There's a great (computer) science experiment in here waiting to be run.  Setting up a 1-SSD + N-spinning-rust mirror (given the capacity mismatch, one could theoretically use N-slices of N-spinning-rusts) and then measuring read vs. write, which disks used, etc. would be spectacularly useful.  It would also probably make a nice presentation at the next OpenZFS conference.

Speaking of that, this question should be posed on the OpenZFS mailing list.  It's possible someone in the wider ZFS community has considered this or even run tests already.

Dan