Hi Sage, While reading the implementation and the commits related to crush tunables & rule step set_* I got the impression that vary_r[1] introduced early 2014 is a better solution than local_fallback_tries etc. [2] introduced around 2012. Both are helping to select an alternative item when there is a collision. If that's not the case I'll try to research the motivation to set local_fallback_retries = 1 instead of the default value 0 it has in tunables since bobtail[3]. And although nothing forbids using local_fallback_tries = 1 & vary_r = 1, it looks like the vary_r implementation did not take into account that combination. Cheers [1] vary_r https://github.com/ceph/ceph/blob/master/src/crush/mapper.c#L470 [2] local_fallback_tries https://github.com/ceph/ceph/blob/master/src/crush/mapper.c#L479 [3] bobtail tunables https://github.com/ceph/ceph/blob/master/src/crush/CrushWrapper.h#L113 -- Loïc Dachary, Artisan Logiciel Libre -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
