Dear ceph-users,
We want to optimise our crush rules further and to test adjustments
without impact to the cluster, we use crushtool to show the mappings.
eg:
crushtool -i crushmap.16 --test --num-rep 4 --show-mappings --rule
0|tail -n 10
CRUSH rule 0 x 1014 [121,125,195,197]
CRUSH rule 0 x 1015 [20,1,40,151]
CRUSH rule 0 x 1016 [194,244,158,3]
CRUSH rule 0 x 1017 [39,113,242,179]
CRUSH rule 0 x 1018 [131,113,199,179]
CRUSH rule 0 x 1019 [64,63,221,181]
CRUSH rule 0 x 1020 [26,111,188,179]
CRUSH rule 0 x 1021 [125,78,247,214]
CRUSH rule 0 x 1022 [48,125,246,258]
CRUSH rule 0 x 1023 [0,88,237,211]
The osd numbers in brackets are not the full story, of course...
It would be nice to see more info about the location hierarchy that is
in the crushmap, because we want to make sure the redundancy is spread
optimally accross our datacenters and racks/hosts.
In the current output, this requires lookups to find out the locations
for the osds before we can be sure.
Since the info is already known in the crushmap, I was wondering if
someone has already hacked up some wrapper script that looks up the
locations of the osds, or if work is ongoing to add an option to
crushtool to output the locations with the osd numbers?
If not, I might write a wrapper myself...
