You could also set *osd_crush_initial_weight = 0 . *New OSDs will automatically come up with a 0 weight and you won't have to race the clock.
-Brett On Thu, Oct 4, 2018 at 3:50 AM Janne Johansson <icepic...@gmail.com> wrote: > > > Den tors 4 okt. 2018 kl 00:09 skrev Bruno Carvalho <bruno...@gmail.com>: > >> Hi Cephers, I would like to know how you are growing the cluster. >> Using dissimilar hardware in the same pool or creating a pool for each >> different hardware group. >> What problem would I have many problems using different hardware (CPU, >> memory, disk) in the same pool? > > > I don't think CPU and RAM (and other hw related things like HBA controller > card brand) matters > a lot, more is always nicer, but as long as you don't add worse machines > like Jonathan wrote you > should not see any degradation. > > What you might want to look out for is if the new disks are very uneven > compared to the old > setup, so if you used to have servers with 10x2TB drives and suddenly add > one with 2x10TB, > things might become very unbalanced, since those differences will not be > handled seamlessly > by the crush map. > > Apart from that, the only issues for us is "add drives, quickly set crush > reweight to 0.0 before > all existing OSD hosts shoot massive amounts of I/O on them, then script a > slower raise of > crush weight upto what they should end up at", to lessen the impact for > our 24/7 operations. > > If you have weekends where noone accesses the cluster or night-time low-IO > usage patterns, > just upping the weight at the right hour might suffice. > > Lastly, for ssd/nvme setups with good networking, this is almost moot, > they converge so fast > its almost unfair. A real joy working with expanding flash-only > pools/clusters. > > -- > May the most significant bit of your life be positive. > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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