I often add 50+ OSDs at a time and my cluster is all NLSAS. Here is what I do, 
you can obviously change the weight increase steps to what you are comfortable 
with. This has worked well for me and my workloads. I've sometimes seen peering 
take longer if I do steps too quickly but I don't run any mission critical has 
to be up 100% stuff and I usually don't notice if a pg takes a while to peer.

Add all OSDs with an initial weight of 0. (nothing gets remapped)
Ensure cluster is healthy.
Use a for loop to increase weight on all news OSDs to 0.5 with a generous sleep 
between each for peering.
Let the cluster balance and get healthy or close to healthy.
Then repeat the previous 2 steps increasing weight by +0.5 or +1.0 until I am 
at the desired weight.

Kevin

On 7/24/19 11:44 AM, Xavier Trilla wrote:
Hi,

What would be the proper way to add 100 new OSDs to a cluster?

I have to add 100 new OSDs to our actual > 300 OSDs cluster, and I would like 
to know how you do it.

Usually, we add them quite slowly. Our cluster is a pure SSD/NVMe one, and it 
can handle plenty of load, but for the sake of safety -it hosts thousands of 
VMs via RBD- we usually add them one by one, waiting for a long time between 
adding each OSD.

Obviously this leads to PLENTY of data movement, as each time the cluster 
geometry changes, data is migrated among all the OSDs. But with the kind of 
load we have, if we add several OSDs at the same time, some PGs can get stuck 
for a while, while they peer to the new OSDs.

Now that I have to add > 100 new OSDs I was wondering if somebody has some 
suggestions.

Thanks!
Xavier.



_______________________________________________
ceph-users mailing list
ceph-users@lists.ceph.com<mailto:ceph-users@lists.ceph.com>
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com


_______________________________________________
ceph-users mailing list
ceph-users@lists.ceph.com
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com

Reply via email to