Now that’s a *very* different question from numbers assigned during an install. With recent releases instead of going down the full removal litany listed below, you can instead down/out the OSD and `destroy` it. That preserves the CRUSH bucket and OSD ID, then when you use ceph-disk, ceph-volume, what-have-you to deploy a replacement, you can specify the same and desired OSD ID on the commandline. Note that as of 12.2.2, you’ll want to record and re-set any override reweight (manual or reweight-by-utilization) as that usually or never survives. Also note that again as of that release, if the replacement drive is a different size, the CRUSH weight is not adjusted, so you may (or may not) want to adjust the CRUSH weight. Slight differences aren’t usually a huge deal; big differences can mean you have unused capacity, or overloaded drives. — Anthony > > Thank you for your answer below. > > I'm not looking to reuse them as much as I am trying to control what unused number is actually used. > > For example if I have 20 osds and 2 have failed...when I replace a disk in one server I don't want it to automatically use the next lowest number for the osd assignment. > > I understand what you mean about not focusing on the osd ids...but my ocd is making me ask the question. > > Thanks, > Shain > > On 9/11/20, 9:45 AM, "George Shuklin" <george.shuklin@xxxxxxxxx> wrote: > > On 11/09/2020 16:11, Shain Miley wrote: >> Hello, >> I have been wondering for quite some time whether or not it is possible to influence the osd.id numbers that are assigned during an install. >> >> I have made an attempt to keep our osds in order over the last few years, but it is a losing battle without having some control over the osd assignment. >> >> I am currently using ceph-deploy to handle adding nodes to the cluster. >> > You can reuse osd numbers, but I strongly advice you not to focus on > precise IDs. The reason is that you can have such combination of server > faults, which will swap IDs no matter what. > > It's a false sense of beauty to have 'ID of OSD match ID in the name of > the server'. > > How to reuse osd nums? > > OSD number is used (and should be cleaned if OSD dies) in three places > in Ceph: > > 1) Crush map: ceph osd crush rm osd.x > > 2) osd list: ceph osd rm osd.x > > 3) auth: ceph auth rm osd.x > > The last one is often forgoten and is a usual reason for ceph-ansible to > fail on new disk in the server. > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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