On Wed, Apr 29, 2015 at 6:06 PM, Paul Evans <paul@xxxxxxxxxxxx> wrote: > In one of our clusters we sometimes end up with PGs that are mapped > incorrectly and settle into a ‘remapped’ state (forever). Is there a way to > nudge a specific PG to recalculate placement and relocate the data? One > option that we’re *dangerously* unclear about is the use of ceph pg > force_create_pg <pgid>. Is this a viable command to use in a ‘remapped’ > situation? Remapped PGs that are stuck that way mean that CRUSH is failing to map them appropriately — I think we talked about the circumstances around that previously. :) So nudging CRUSH can't do anything; it will just fail to map them appropriately again. (And indeed this is what happens whenever anyone does something to that PG or the OSD Map gets changed.) The force_create_pg command does exactly what it sounds like: it tells the OSDs which should currently host the named PG to create it. You shouldn't need to run it and I don't remember exactly what checks it goes through, but it's generally for when you've given up on retrieving any data out of a PG whose OSDs died and want to just start over with a completely blank one. -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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