On Sun, Feb 15, 2015 at 06:24:45PM -0800, Sage Weil wrote: > On Sun, 15 Feb 2015, Gregory Farnum wrote: > > On Sun, Feb 15, 2015 at 5:39 PM, Sage Weil <sage@xxxxxxxxxxxx> wrote: > > > On Sun, 15 Feb 2015, Mykola Golub wrote: .... > > >> https://github.com/trociny/ceph/compare/wip-osd_create > > > > > > This looks reasonable to me! > > > > > > Do you mind adding a few test cases in qa/workunits/cephtool/test.sh to go > > > along with it? Will do. Thanks. > > > > > > Usual disclaimer: we discourage getting creative with the osd ids because > > > they are allocated as an *array* in memory, so skipping entries consumes > > > some extra memory.. this can become significant if there are large > > > gaps and/or clusters are large. > > > > These options used to exist and were removed quite deliberately. I > > don't remember the entire conversation at this point but we'll need to > > find and address the concerns raised then before reintroducing the > > ability to explicitly set OSD IDs. IIRC I was on the losing end of > > this, because it's definitely behavior we should be offering to > > admins, but the issues were significant enough we had to eliminate the > > option. Methods of preserving the user-facing utility like adding OSD > > names were deemed too difficult to implement. :( > > > > (I think it largely had to do with serious issues over the > > availability and location of data when OSDs disappear, but new ones > > with the same ID are present. And what you do when somebody then > > resurrects the original OSDs. But there might have been other things > > too.) > > The part I remember was just that 'ceph osd create <id>' wasn't a use and > idempotent command. I don't think reusing ids is the problem, though if > it is then it is still a problem since osd create will re-use the first > available id. I think all this option lets us do that we didn't before is > leave gaps in the id space? I think so too -- leaving gaps should be the only difference comparing to what we already have. I was wandering though if I might need to do something with those nonexistent IDs in the gap, e.g. pre-allocating them explicitly with some flags combination. It looks like I don't... -- Mykola Golub _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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