Check out http://ceph.com/docs/master/rados/operations/pools/#set-pool-values "Hit sets" are bloom filters which we use to track which objects are accessed ("hit") during a specific time period (hit_set_period). More hit sets within a given time let us distinguish more fine-grained accesses to them, but require more tracking space. If you're trying to flush dirty data out of the cache pool more quickly, you'll want to adjust the dirty age values more than the hit set values. -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com On Mon, Aug 11, 2014 at 7:11 PM, ????????? ??????? <v1t83 at yandex.ru> wrote: > Hi! > I can not understand the meaning of the parameter hit_set_period. This is the minimum time then begin flush changed data from cache to based pool? Or this time after which the not changed data is deleted from cache pool? > For example: there is a pool main_pool on 4 OSD and ssd_pool on ssd disk. I set the cache ssd_pool for main_pool and set hit_set_period 3600. Begin write a virtual machine to main_pool. After some time the image of the virtual machine will be located on the main pool? I want know, what period of time i lost data then ssd will break. > Thank > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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