On Tue, 12 Jul 2016 12:50:26 +0200 (CEST) Wido den Hollander wrote: > > > Op 12 juli 2016 om 12:35 schreef Simon Murray <simon.murray@xxxxxxxxxxxxxxxxx>: > > > > > > Hi all. > > > > I'm about to perform a rather large reorganization of our cluster and > > thought I'd get some insight from the community before going any further. > > > > The current state we have (logically) is two trees, one for spinning rust, > > one for SSD. Chassis are the current failure domain, and are all chassis > > types are organized under a single rack. > > > > The machines have been physically been relocated across 4 racks and I have > > re-written the crush map to organize it so the chassis are correctly > > located in the correct racks. I intend to also change the rules so that > > the failure domain is now at the rack level so we can tolerate more severe > > power and switching failure. > > It might be just me, but all my production gear always has 2 PSUs, hanging of 2 independent PDUs and of course 2 switches. The notion of a rack for me is just something that happens to other people. ^o^ > > Question is how is the best way to do this? > > > > 1) The pragmatist in me says commit the new crush map, let things > > rebalance, then apply a new rule set to each pool and again let things > > rebalance. > > > > Yes, that would be easy to do. Also, you can always revert to the old situation if you need to. > > > 2) It would however mean much less scheduled maintenance and keep customers > > happier if I could just do everything as a big bang and do everything at > > once e.g. rename the existing rule sets to replicated_rack_leaf(_ssd), and > > change the chooseleaf option to type rack, and hope for the best :) > > > > Is the latter safe or just plain crazy? > > A big change can be easier for Ceph. You simply limit the backfill and recovery to one at a time and let it run. > > You could also create new rulesets which do the mapping in a different way and switch per pool to the new rulesets. > That's what I would most likely do as well. Christian > Wido > > > > > Si > > > > -- > > DataCentred Limited registered in England and Wales no. 05611763 > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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