CephNotes

Some notes about Ceph
Laurent Barbe @Adelius / INRAE

Ceph Versions: Open Source / RHCS / IBM

Release Date Version (Community) Red Hat Ceph Storage IBM Storage Ceph
2024-09-26 Ceph 19.2 "Squid" RHCS 8 IBM Storage Ceph 8
2023-08-07 Ceph 18.2 "Reef" RHCS 7 IBM Storage Ceph 7
2022-04-19 Ceph 17.2 "Quincy" RHCS 6 IBM Storage Ceph 6
2021-03-31 Ceph 16.2 "Pacific" RHCS …

RBD journal offloading

If you are using rbd journaling feature (for example for rbd mirroring), in some cases it could be interesting to offloading journaling on specific pool. For example if your rbd pool is on hdd drives and you also have ssd or nvme.

external rbd journal

To change rbd journaling pool, there are 2 …

How many mouvement when I add a replica ?

Make a simple simulation !

Use your own crushmap :

$ ceph osd getcrushmap -o crushmap

got crush map from osdmap epoch 28673

Or create a sample clushmap :

$ crushtool --outfn crushmap --build --num_osds 36 host straw 12 root straw 0

2017-07-28 15:01:16.240974 7f4dda123760  1 
ID  WEIGHT  TYPE NAME
-4 …